Fix agent tips not appearing below the warping indicator (warpdotdev#13122)

## Description
The rotating agent tips that normally render below the "Warping..." text
in Agent Mode stopped appearing.

**Root cause:** PR warpdotdev#9297 (commit `76cccd24d`, "Clip warping-indicator
chips so they don't overflow narrow panes") wrapped the warping
indicator's row in a `Clipped` element so the action chips don't
overflow into the adjacent pane on narrow widths. That row sits inside a
`ConstrainedBox` whose height was already fixed to a single line of
text. Before the clip was added, the tip rendered on a second line and
simply overflowed the fixed-height box visibly. Once the row was clipped
to the box's bounds, that second line — the agent tip (and the
fallback-model explanation, which uses the same `secondary_element`
slot) — was clipped away entirely.

**Fix:** In `render_warping_indicator_base`
(`app/src/ai/blocklist/block/view_impl/common.rs`), reserve room for the
secondary line in the footer height when a `secondary_element` is
present, so the clip no longer hides it while still clipping the chips
horizontally as intended. The height math is extracted into a small pure
helper `warping_footer_height(monospace_font_size,
has_secondary_element)`.

## Linked Issue
Reported in Slack (factory-client bug-triage): see thread link below. No
GitHub issue.

## Testing
- Added a regression unit test
`warping_footer_height_reserves_a_line_for_the_secondary_element` in
`common_tests.rs` that asserts the footer reserves an extra line
(secondary font size + 1px margin) when a secondary element is present.
It fails against the old single-line height and passes with the fix.
- `cargo nextest run -p warp warping_footer_height` — passes.
- `cargo clippy -p warp --lib --no-deps` — clean.
- **Manual UI verification (computer use) on a running debug build —
done.** Launched the authenticated `warp` build, started an agent, and
confirmed:
- Normal width: a tip line renders directly below `Warping...` (e.g.
`Tip: /new to start a new agent conversation with clean context. Learn
more`) and is fully visible, not clipped. Tips rotate as expected.
- Narrow pane: the tip still renders (horizontally ellipsized to fit)
and the action chips stay within the pane — i.e. warpdotdev#9297's chip-clipping
is preserved alongside the restored tip.
- Screenshots (normal + narrow width) are attached in the linked Slack
thread.

### Screenshots / Videos
Verification screenshots (normal-width tip restored; narrow-pane tip +
chips) are posted in the linked Slack thread below.

## Agent Mode
- [x] Warp Agent Mode - This PR was created via Warp's AI Agent Mode

<!--
CHANGELOG-BUG-FIX: Fix the rotating agent tips not appearing below the
"Warping..." indicator in Agent Mode.
-->
CHANGELOG-BUG-FIX: Fix the rotating agent tips not appearing below the
"Warping..." indicator in Agent Mode.

_Slack thread:
https://warpdev.slack.com/archives/C0BCE7AELJ2/p1782518640801369?thread_ts=1782518640.801369&cid=C0BCE7AELJ2_

<!-- factory-client:
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-->

Co-authored-by: Oz <oz-agent@warp.dev>

Author: warp-agent-staging[bot]

app/src/ai/blocklist/block/view_impl/common.rs

@@ -526,6 +526,23 @@ pub struct WarpingIndicatorProps {
     pub secondary_element: Option<Box<dyn Element>>,
 }
 
+/// Computes the fixed height of the warping-indicator footer.
+///
+/// The warping text occupies a single line. When a secondary element (an agent
+/// tip or fallback-model explanation) is present, it renders on a second line
+/// below the warping text, so the footer must reserve room for that extra line;
+/// otherwise the `Clipped` wrapper — which keeps action chips from overflowing
+/// narrow panes — also clips the secondary line. The extra line accounts for the
+/// secondary element's font size (`monospace_font_size - 3`, see
+/// `render_agent_tip` / `render_fallback_explanation`) plus its 1px top margin.
+fn warping_footer_height(monospace_font_size: f32, has_secondary_element: bool) -> f32 {
+    let mut height = STATUS_FOOTER_VERTICAL_PADDING * 2. + monospace_font_size;
+    if has_secondary_element {
+        height += (monospace_font_size - 3.) + 1.;
+    }
+    height
+}
+
 /// Helper function to render text in the "warping..." footer.
 /// Additional text that does not use the shimmering text animation can be passed in via
 /// `non_shimmering_text` which is useful if you want some part of the text to constantly update
@@ -543,6 +560,10 @@ pub fn render_warping_indicator_base(
         is_passive_code_diff,
         secondary_element,
     } = props;
+    // Whether a secondary element (an agent tip or fallback-model explanation)
+    // will be rendered on a second line below the warping text. Captured before
+    // `secondary_element` is consumed so the container can reserve room for it.
+    let has_secondary_element = secondary_element.is_some();
     // Unicode code point for the Warp glyph that is embedded in the version of Roboto we bundle
     // into the app. This code point MUST be rendered using Roboto (the default ui font) or else the
     // glyph may not be rendered.
@@ -646,7 +667,10 @@ pub fn render_warping_indicator_base(
     } else {
         let mut container = Container::new(
             ConstrainedBox::new(content)
-                .with_height(STATUS_FOOTER_VERTICAL_PADDING * 2. + appearance.monospace_font_size())
+                .with_height(warping_footer_height(
+                    appearance.monospace_font_size(),
+                    has_secondary_element,
+                ))
                 .finish(),
         )
         .with_padding_right(CONTENT_HORIZONTAL_PADDING);

app/src/ai/blocklist/block/view_impl/common_tests.rs

@@ -17,8 +17,8 @@ use super::{
     collect_visual_markdown_lightbox_collection, compute_visual_section_width,
     image_tooltip_handles_for_group, inline_image_source_label,
     is_supported_blocklist_image_source, lightbox_trigger_for_section, query_prefix_highlight_len,
-    render_scrollable_collapsible_content, text_sections_with_indices, CollapsibleElementState,
-    CollapsibleExpansionState, VisualMarkdownLightboxCollection,
+    render_scrollable_collapsible_content, text_sections_with_indices, warping_footer_height,
+    CollapsibleElementState, CollapsibleExpansionState, VisualMarkdownLightboxCollection,
 };
 use crate::ai::agent::{
     AIAgentInput, AIAgentTextSection, AgentOutputImage, AgentOutputImageLayout,
@@ -161,6 +161,26 @@ fn render_scrollable_collapsible_content_returns_none_when_collapsed() {
     );
 }
 
+#[test]
+fn warping_footer_height_reserves_a_line_for_the_secondary_element() {
+    // Regression: the warping indicator's footer is a fixed-height, clipped
+    // container. When an agent tip (or fallback-model explanation) is present it
+    // renders on a second line, so the footer must be taller than the
+    // single-line case — otherwise the clip (added to keep action chips from
+    // overflowing narrow panes) hides the tip entirely.
+    let font_size = 13.;
+    let without_tip = warping_footer_height(font_size, false);
+    let with_tip = warping_footer_height(font_size, true);
+
+    assert!(
+        with_tip > without_tip,
+        "footer with a secondary element ({with_tip}) should be taller than without ({without_tip})",
+    );
+    // The extra room must cover the secondary line: its font size
+    // (monospace_font_size - 3) plus the 1px top margin on the tip container.
+    assert_eq!(with_tip - without_tip, (font_size - 3.) + 1.);
+}
+
 #[test]
 fn compute_visual_section_width_rejects_non_finite_dimensions() {
     assert_eq!(compute_visual_section_width(f32::INFINITY, 20., 40.), None);