refactor(ui): decouple chat liveness blue from status token via --liveness-blue (A6)

IssueChatThread's human-message bubble reused --status-task-in_progress
(Batch 1; the shared #2563eb is a semantic coincidence, not a real
dependency). Mint --liveness-blue: #2563eb in the extracted-tokens block
and re-point the bubble class plus the lockstep negative assertion in
IssueChatThread.test.tsx, so a future status-hue change no longer drags
the chat bubble along. Same value today — zero rendered-output change.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ui/src/components/IssueChatThread.test.tsx

@@ -1756,8 +1756,8 @@ describe("IssueChatThread", () => {
     expect(bubble?.textContent).toContain("Here is my agent reply.");
     expect(bubble?.className).toContain("max-w-(--sz-calc-7)");
     expect(bubble?.className).toContain("sm:max-w-(--pct-85)");
-    // Neutral, not the human liveness-blue bubble.
-    expect(bubble?.className).not.toContain("bg-(--status-task-in_progress)");
+    // Neutral, not the human liveness-blue bubble (--liveness-blue, DECISION-SHEET.md A6).
+    expect(bubble?.className).not.toContain("bg-(--liveness-blue)");
 
     act(() => {
       root.unmount();

ui/src/components/IssueChatThread.tsx

@@ -1447,8 +1447,9 @@ function IssueChatUserMessage({
             : deleted
               ? "bg-muted/50 text-muted-foreground"
             : isCurrentUser
-              // Liveness blue (--status-task-in_progress) for the human's own messages (PAP-95 rev 5).
-              ? "bg-(--status-task-in_progress) text-white"
+              // Liveness blue (--liveness-blue, decoupled from --status-task-in_progress
+              // in DECISION-SHEET.md A6) for the human's own messages (PAP-95 rev 5).
+              ? "bg-(--liveness-blue) text-white"
               : "bg-muted",
           pending && "opacity-80",
         )}

ui/src/index.css

@@ -1465,6 +1465,7 @@ span.paperclip-mention-chip[data-mention-kind="external-object"] {
   --hex-10b981: #10b981; /* ActivityCharts.tsx — status 'done'; also the >=0.8 success-rate bar tint. */
   --project-none: #64748b; /* Semantic rename of --hex-64748b (DECISION-SHEET.md A3, value unchanged). 'No project assigned' muted-slate fallback (TOKEN-AUDIT.md 1.3) across Routines/MarkdownEditor/RoutineRunVariablesDialog/RoutineList/IssueColumns/editable-sections; also ActivityCharts.tsx status 'backlog'. */
   --project-seed: #6366f1; /* Semantic rename of --hex-6366f1 (DECISION-SHEET.md A3, value unchanged). Project-color-fallback indigo seed default (ProjectDetail/PipelineSettings/IssueProperties/NewIssueDialog) — new-project-color-picker-seed family per TOKEN-AUDIT.md 1.3. */
+  --liveness-blue: #2563eb; /* DECISION-SHEET.md A6: IssueChatThread.tsx human-message 'liveness blue' bubble (PAP-95 rev 5). Same value as --status-task-in_progress by coincidence, decoupled on purpose so a future status-hue change doesn't drag the chat bubble along. */
   --gradient-extract-1: linear-gradient(180deg,rgba(255,80,80,0.12),rgba(255,255,255,0.02)); /* Dashboard.tsx budget-alert card gradient. */
   --gradient-extract-2: linear-gradient(180deg,rgba(255,255,255,0.05),rgba(255,255,255,0.02)); /* Costs.tsx subtle white card gradient. */
   --gradient-extract-3: radial-gradient(circle at top left,rgba(244,114,182,0.08),transparent 35%),radial-gradient(circle at bottom right,rgba(56,189,248,0.1),transparent 32%); /* AccountingModelCard.tsx decorative overlay. */