fix: allow anonymous access to /invite/:token accept page (Stirling-Tools#7612)

## Problem

In the self-hosted build with login enabled, admin-generated invite
links point to the SPA route `/invite/<token>`, but that route is not
covered by the anonymous whitelist. Anonymous users get 401 / redirected
to `/login` before the React app can mount - even though the APIs the
page calls (`/api/v1/invite/validate`, `/api/v1/invite/accept`) are
already whitelisted. Since accepting an invite is how a *new* account is
created, requiring authentication first makes the feature unusable.

## Fix

Add `INVITE_LINK_PATTERN` (`^/invite/[^/]+/?$`) in
`RequestUriUtils.java`, matched at the end of `isPublicAuthEndpoint()` -
mirroring the existing `SHARE_LINK_PATTERN` handling. The invite data
APIs remain protected by their own token validation; only the SPA
bootstrap page becomes anonymously reachable.

## Tests

Added unit tests in `RequestUriUtilsTest.java` mirroring the share-link
tests:

- `/invite/<token>` (with/without trailing slash, with context path) ?
public
- bare `/invite` and `/invite/` ? NOT public (token segment required)
- `/invite/<token>/foo` nested paths ? NOT public
- `/inviteX` prefix over-match ? NOT public

## Verification

Pattern behavior validated against all test cases above. Live-tested on
2.14.3 self-hosted: anonymous `GET /invite/<token>` returned 401 before
the fix; the whitelisted accept flow itself (`validate` + `accept` APIs)
works anonymously end-to-end.

Author: admiralXS

app/common/src/main/java/stirling/software/common/util/RequestUriUtils.java

@@ -5,6 +5,10 @@
 public class RequestUriUtils {
 
     private static final Pattern SHARE_LINK_PATTERN = Pattern.compile("^/share/[^/]+/?$");
+    // Invite tokens are 36-char lowercase UUIDs (UUID.randomUUID().toString()); match exactly
+    private static final Pattern INVITE_LINK_PATTERN =
+            Pattern.compile(
+                    "^/invite/[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/?$");
 
     public static boolean isStaticResource(String requestURI) {
         return isStaticResource("", requestURI);
@@ -209,7 +213,9 @@ public static boolean isPublicAuthEndpoint(String requestURI, String contextPath
                 // Workflow participant endpoints - access controlled by share tokens, not login
                 || trimmedUri.startsWith("/api/v1/workflow/participant/")
                 // Share-link SPA bootstrap; data APIs remain protected
-                || SHARE_LINK_PATTERN.matcher(trimmedUri).matches();
+                || SHARE_LINK_PATTERN.matcher(trimmedUri).matches()
+                // Invite-accept SPA bootstrap; data APIs remain protected
+                || INVITE_LINK_PATTERN.matcher(trimmedUri).matches();
     }
 
     private static String stripContextPath(String contextPath, String requestURI) {

app/common/src/test/java/stirling/software/common/util/RequestUriUtilsTest.java

@@ -236,4 +236,86 @@ void testIsPublicAuthEndpoint_shareApiStillProtected() {
                 RequestUriUtils.isPublicAuthEndpoint(
                         "/api/v1/storage/share-links/abc123/metadata", ""));
     }
+
+    // --- invite-accept SPA bootstrap ---
+
+    private static final String INVITE_TOKEN = "06a20e7e-2e35-4e26-be7d-2dce14f28f12";
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteLinkToken() {
+        assertTrue(RequestUriUtils.isPublicAuthEndpoint("/invite/" + INVITE_TOKEN, ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteLinkTokenTrailingSlash() {
+        assertTrue(RequestUriUtils.isPublicAuthEndpoint("/invite/" + INVITE_TOKEN + "/", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteLinkWithContextPath() {
+        assertTrue(RequestUriUtils.isPublicAuthEndpoint("/app/invite/" + INVITE_TOKEN, "/app"));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteRootNotPublic() {
+        // Avoid matching bare "/invite" or "/invite/" - must have a token segment
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite", ""));
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteNestedPathNotPublic() {
+        // Guard against future additions like /invite/<token>/foo becoming accidentally public
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/" + INVITE_TOKEN + "/foo", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_invitePrefixDoesNotOvermatch() {
+        // "/inviteX" must not match the invite pattern
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/inviteX", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteNonUuidTokenNotPublic() {
+        // Only exactly-shaped 36-char lowercase UUID tokens are treated as invite links
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/abc123", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteUppercaseUuidNotPublic() {
+        // Tokens are generated lowercase by UUID.randomUUID().toString()
+        assertFalse(
+                RequestUriUtils.isPublicAuthEndpoint(
+                        "/invite/06A20E7E-2E35-4E26-BE7D-2DCE14F28F12", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteWrongLengthNotPublic() {
+        // 35-char and 37-char UUID-like tokens are not valid UUIDs
+        assertFalse(
+                RequestUriUtils.isPublicAuthEndpoint(
+                        "/invite/06a20e7e-2e35-4e26-be7d-2dce14f28f1", ""));
+        assertFalse(
+                RequestUriUtils.isPublicAuthEndpoint(
+                        "/invite/06a20e7e-2e35-4e26-be7d-2dce14f28f122", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteWrongGroupingNotPublic() {
+        // Groups of 8-4-4-4-4 must not be shifted around (e.g. 4-4-4-4-8)
+        assertFalse(
+                RequestUriUtils.isPublicAuthEndpoint(
+                        "/invite/06a2-0e7e-2e35-4e26-be7d2dce14f28f12", ""));
+    }
+
+    @Test
+    void testIsPublicAuthEndpoint_inviteTokenInvalidCharsNotPublic() {
+        // Hex-only; anything outside [0-9a-f] or the UUID hyphens is rejected
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/abc$123", ""));
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/abc..123", ""));
+        assertFalse(RequestUriUtils.isPublicAuthEndpoint("/invite/abc%2F123", ""));
+        assertFalse(
+                RequestUriUtils.isPublicAuthEndpoint(
+                        "/invite/06a20e7e-2e35-4e26-be7d-2dce14f28f1g", ""));
+    }
 }