SIG-2 Address review round 4: M3 bridge slots, sheet modality, a11y, test fixes

Theme bridge (Theme.kt, Type.kt):
- Map the M3 slots existing screens read but the bridge left at baseline:
  tertiary -> warn (signing chip), secondary -> good (signed/broadcast
  chips; was duplicating onSurface), errorContainer/onErrorContainer from
  bad, surfaceContainer* -> surfaceSunken/surface/surfaceElev (filled Card
  and AlertDialog backgrounds in material3 1.3).
- outline was the 8%-alpha hairline: invisible as OutlinedTextField/
  OutlinedButton borders and unreadable as the "deleted" chip text. Now
  textMute (opaque); outlineVariant takes the hairline for dividers.
- Collapse the verbatim-duplicated dark/light mapping into one .copy()
  over the base scheme so the two modes can't drift.
- Set explicit lineHeight on every Vault TextStyle (and on the fontSize-
  changing copies in vaultMaterialTypography): the M3 styles being
  replaced all carry explicit line heights, so leaving lineHeight
  unspecified tightened multi-line text on existing screens.

BottomSheetOverlay:
- Consume taps on the sheet container; clip/background don't block hit
  testing, so taps inside the sheet fell through to the scrim's clickable
  and dismissed the sheet (regression test added).
- BackHandler(enabled = visible): system back now dismisses the sheet
  instead of firing the host screen's handler.
- navigationBarsPadding + imePadding so the keyboard can't cover sheet
  content; paneTitle semantics; KDoc on the overlay-slot constraint and
  the remaining TalkBack limitation (no Popup window).

Accessibility:
- BackButton: 48dp touch target around the 36dp visual (foundation
  clickable gets no Material minimum-size enforcement); use material3
  Icon instead of hand-rolled Image+tint.
- Spinner: progressSemantics() so TalkBack announces the busy state
  (parity with the CircularProgressIndicator it replaces).
- AppButton: focus now shows a visible border; with indication = null the
  press-scale was the only cue, leaving keyboard/D-pad focus invisible.

Tests:
- addr_truncatesLong expected "bc1qme…qmlv6" but Addr renders
  "bc1qme…lqmlv6" (takeLast(6) of the fixture is "lqmlv6").
- Disabled-button test asserted assertHasNoClickAction(), which fails on
  foundation 1.7.6 where applySemantics adds onClick unconditionally and
  only gates disabled() on enabled; assert the Disabled flag instead.

Co-Authored-By: Claude Fable 5 (1M context) <noreply@anthropic.com>

Author: forge-welldone

app/src/androidTest/kotlin/com/remotesigner/ui/components/PrimitivesTest.kt

@@ -7,7 +7,6 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.testTag
-import androidx.compose.ui.test.assertHasNoClickAction
 import androidx.compose.ui.test.assertIsDisplayed
 import androidx.compose.ui.test.assertIsNotEnabled
 import androidx.compose.ui.test.junit4.createComposeRule
@@ -72,17 +71,17 @@ class PrimitivesTest(private val darkTheme: Boolean) {
     }
 
     @Test
-    fun appButton_disabled_exposesNoClickAction() {
-        // Compose's `clickable(enabled = false)` strips the OnClick semantics
-        // action, so calling performClick() on the disabled node would fail
-        // the test outright. Verify the disabled state instead.
+    fun appButton_disabled_isNotEnabled() {
+        // Foundation 1.7's clickable adds the OnClick semantics action even
+        // when disabled (only the Disabled flag is gated on `enabled`), so
+        // asserting the absence of a click action would fail. The disabled
+        // flag is the reliable contract.
         setThemedContent {
             AppButton(text = "Disabled", onClick = {}, enabled = false)
         }
         composeTestRule.onNodeWithText("Disabled")
             .assertIsDisplayed()
             .assertIsNotEnabled()
-            .assertHasNoClickAction()
     }
 
     @Test
@@ -131,7 +130,7 @@ class PrimitivesTest(private val darkTheme: Boolean) {
         setThemedContent {
             Addr(value = "bc1qmek5jz2m9l4k6s7yqfdjl2mxv3lqmlv6", head = 6, tail = 6)
         }
-        composeTestRule.onNodeWithText("bc1qme…qmlv6", substring = true).assertIsDisplayed()
+        composeTestRule.onNodeWithText("bc1qme…lqmlv6", substring = true).assertIsDisplayed()
     }
 
     @Test
@@ -170,6 +169,29 @@ class PrimitivesTest(private val darkTheme: Boolean) {
         assertEquals(1, dismissed)
     }
 
+    @Test
+    fun bottomSheet_tapOnSheetBody_doesNotDismiss() {
+        // Regression: the sheet container must consume taps — without it,
+        // taps inside the sheet fall through to the scrim and dismiss.
+        var dismissed = 0
+        setThemedContent {
+            Box(Modifier.fillMaxSize()) {
+                BottomSheetOverlay(
+                    visible = true,
+                    onDismiss = { dismissed++ },
+                ) {
+                    androidx.compose.material3.Text(
+                        "Sheet body",
+                        modifier = Modifier.testTag("body"),
+                    )
+                }
+            }
+        }
+        composeTestRule.onNodeWithTag("body").performClick()
+        composeTestRule.waitForIdle()
+        assertEquals(0, dismissed)
+    }
+
     @Test
     fun appLogo_renders() {
         setThemedContent {

app/src/main/kotlin/com/remotesigner/ui/components/AppButton.kt

@@ -6,6 +6,7 @@ import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsFocusedAsState
 import androidx.compose.foundation.interaction.collectIsPressedAsState
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -49,6 +50,7 @@ fun AppButton(
     val height = if (small) 40.dp else 52.dp
     val interactionSource = remember { MutableInteractionSource() }
     val isPressed by interactionSource.collectIsPressedAsState()
+    val isFocused by interactionSource.collectIsFocusedAsState()
     val scale by animateFloatAsState(if (isPressed && enabled) 0.98f else 1f, label = "btnScale")
 
     val (bg, fg, border) = when (variant) {
@@ -57,6 +59,10 @@ fun AppButton(
         AppButtonVariant.Ghost -> Triple(Color.Transparent, colors.text, null)
         AppButtonVariant.Danger -> Triple(Color.Transparent, colors.bad, BorderStroke(1.dp, colors.bad))
     }
+    // `indication = null` suppresses the ripple, so keyboard/D-pad focus needs
+    // its own visual cue: a text-tinted border readable on every variant bg.
+    val effectiveBorder =
+        if (isFocused) BorderStroke(2.dp, colors.text.copy(alpha = 0.6f)) else border
 
     Box(
         modifier = modifier
@@ -65,7 +71,7 @@ fun AppButton(
             .graphicsLayer { scaleX = scale; scaleY = scale }
             .alpha(if (enabled) 1f else 0.45f)
             .clip(shapes.pill)
-            .let { if (border != null) it.border(border, shapes.pill) else it }
+            .let { if (effectiveBorder != null) it.border(effectiveBorder, shapes.pill) else it }
             .background(bg)
             .clickable(
                 interactionSource = interactionSource,

app/src/main/kotlin/com/remotesigner/ui/components/BottomSheet.kt

@@ -1,16 +1,20 @@
 package com.remotesigner.ui.components
 
+import androidx.activity.compose.BackHandler
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.animation.slideInVertically
 import androidx.compose.animation.slideOutVertically
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.navigationBarsPadding
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.runtime.Composable
@@ -19,8 +23,11 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.semantics.Role
+import androidx.compose.ui.semantics.paneTitle
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.unit.dp
 import com.remotesigner.ui.motion.tweenFade
 import com.remotesigner.ui.motion.tweenSlideUp
@@ -29,6 +36,18 @@ import com.remotesigner.ui.theme.LocalVaultShapes
 
 const val BOTTOM_SHEET_SCRIM_TAG = "bottomSheetScrim"
 
+/**
+ * Vault-styled modal sheet. Place it as the last child of a full-screen `Box`
+ * overlay slot — the overlay measures at full size even while hidden, so it is
+ * not meant to sit inside a `Column`/`Row`.
+ *
+ * Dismissal: scrim tap and system back both call [onDismiss]. The sheet body
+ * consumes taps so touches inside it never reach the scrim.
+ *
+ * Known limitation: the overlay lives in the host window (no Popup), so
+ * TalkBack can still traverse content behind the open sheet. Full modality
+ * needs a Popup/Dialog rewrite, which requires on-device validation.
+ */
 @Composable
 fun BottomSheetOverlay(
     visible: Boolean,
@@ -39,6 +58,7 @@ fun BottomSheetOverlay(
     val colors = LocalVaultColors.current
     val shapes = LocalVaultShapes.current
     val noIndication = remember { MutableInteractionSource() }
+    BackHandler(enabled = visible, onBack = onDismiss)
     Box(modifier = modifier.fillMaxSize()) {
         AnimatedVisibility(
             visible = visible,
@@ -70,6 +90,13 @@ fun BottomSheetOverlay(
                     .fillMaxWidth()
                     .clip(RoundedCornerShape(topStart = shapes.radiusCard, topEnd = shapes.radiusCard))
                     .background(colors.surfaceElev)
+                    // Consume taps: clip/background don't block hit-testing, so
+                    // without this, taps on the sheet body would fall through to
+                    // the scrim's clickable and dismiss the sheet.
+                    .pointerInput(Unit) { detectTapGestures { } }
+                    .semantics { paneTitle = "Sheet" }
+                    .navigationBarsPadding()
+                    .imePadding()
                     .padding(20.dp),
             ) {
                 content()

app/src/main/kotlin/com/remotesigner/ui/components/ScreenHeader.kt

@@ -9,12 +9,12 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.material3.Icon
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
-import androidx.compose.ui.graphics.vector.rememberVectorPainter
 import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.unit.dp
 import com.remotesigner.ui.icons.AppIcons
@@ -55,20 +55,29 @@ fun ScreenHeader(
 private fun BackButton(onClick: () -> Unit) {
     val colors = LocalVaultColors.current
     val shapes = LocalVaultShapes.current
-    val painter = rememberVectorPainter(image = AppIcons.ChevronLeft)
+    // 48dp interactive area (accessibility minimum touch target) around the
+    // 36dp visual; plain foundation clickable gets no Material minimum-size
+    // enforcement, so the touch target must be sized explicitly.
     Box(
         modifier = Modifier
-            .size(36.dp)
+            .size(48.dp)
             .clip(shapes.small)
-            .border(1.dp, colors.line, shapes.small)
             .clickable(role = Role.Button, onClick = onClick),
         contentAlignment = Alignment.Center,
     ) {
-        androidx.compose.foundation.Image(
-            painter = painter,
-            contentDescription = "Back",
-            colorFilter = androidx.compose.ui.graphics.ColorFilter.tint(colors.text),
-            modifier = Modifier.size(16.dp),
-        )
+        Box(
+            modifier = Modifier
+                .size(36.dp)
+                .clip(shapes.small)
+                .border(1.dp, colors.line, shapes.small),
+            contentAlignment = Alignment.Center,
+        ) {
+            Icon(
+                imageVector = AppIcons.ChevronLeft,
+                contentDescription = "Back",
+                tint = colors.text,
+                modifier = Modifier.size(16.dp),
+            )
+        }
     }
 }

app/src/main/kotlin/com/remotesigner/ui/components/Spinner.kt

@@ -2,6 +2,7 @@ package com.remotesigner.ui.components
 
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.progressSemantics
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
@@ -26,7 +27,9 @@ fun Spinner(
     val rotation by rememberSsSpin()
     val tint = color ?: colors.accent
     val stroke = strokeWidth
-    Canvas(modifier = modifier.size(size)) {
+    // progressSemantics exposes an indeterminate ProgressBarRangeInfo so
+    // TalkBack announces the busy state (parity with CircularProgressIndicator).
+    Canvas(modifier = modifier.size(size).progressSemantics()) {
         rotate(degrees = rotation) {
             val pad = stroke.toPx()
             val rect = Size(this.size.width - pad * 2, this.size.height - pad * 2)

app/src/main/kotlin/com/remotesigner/ui/theme/Theme.kt

@@ -7,41 +7,46 @@ import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 
-private fun materialFromVault(v: VaultColors) = if (v.isDark) {
-    darkColorScheme(
+// Bridge for the not-yet-migrated Material3 screens: every slot those screens
+// read must resolve to a Vault color, otherwise M3 baseline (purple-tinted)
+// defaults leak through. Single mapping over the base scheme so dark and light
+// can't drift apart.
+//
+// Slot notes:
+// - `secondary` colors the signed/broadcast inbox chips -> good (success).
+// - `tertiary` colors the in-progress "signing" chip -> warn.
+// - `outline` borders OutlinedTextField/OutlinedButton and is read as text by
+//   the "deleted" chip, so it must be opaque -> textMute (v.line at 8% alpha
+//   is invisible as a border and unreadable as text).
+// - `errorContainer` backs PSBT-warning and broadcast-failure cards -> bad
+//   tinted like the Pill tones, with full-strength bad for the text on it.
+// - `surfaceContainer*` back filled Cards and AlertDialogs in material3 1.3.
+private fun materialFromVault(v: VaultColors) =
+    (if (v.isDark) darkColorScheme() else lightColorScheme()).copy(
         primary = v.accent,
         onPrimary = v.accentInk,
-        secondary = v.text,
+        secondary = v.good,
         onSecondary = v.bg,
+        tertiary = v.warn,
+        onTertiary = v.bg,
         background = v.bg,
         onBackground = v.text,
         surface = v.surface,
         onSurface = v.text,
         surfaceVariant = v.surfaceElev,
         onSurfaceVariant = v.textDim,
-        outline = v.line,
-        outlineVariant = v.lineStrong,
+        surfaceContainerLowest = v.surfaceSunken,
+        surfaceContainerLow = v.surface,
+        surfaceContainer = v.surface,
+        surfaceContainerHigh = v.surfaceElev,
+        surfaceContainerHighest = v.surfaceElev,
+        outline = v.textMute,
+        outlineVariant = v.line,
         error = v.bad,
         onError = v.bg,
+        errorContainer = v.bad.copy(alpha = 0.12f),
+        onErrorContainer = v.bad,
     )
-} else {
-    lightColorScheme(
-        primary = v.accent,
-        onPrimary = v.accentInk,
-        secondary = v.text,
-        onSecondary = v.bg,
-        background = v.bg,
-        onBackground = v.text,
-        surface = v.surface,
-        onSurface = v.text,
-        surfaceVariant = v.surfaceElev,
-        onSurfaceVariant = v.textDim,
-        outline = v.line,
-        outlineVariant = v.lineStrong,
-        error = v.bad,
-        onError = v.bg,
-    )
-}
 
 @Composable
 fun SatoshiSignerTheme(