fix: clear remaining full-suite floaters after #2287 (#2288)

## Summary
#2287 cleared most of Full Suite run 29633869887 / post-merge
29634793317. Shards 1 and 2 went green; remaining floaters:

- **TaskDetailModal.css FN-8154** — assert FN-8166 zeroed mobile
`.detail-activity` inset (`padding-inline-end: 0`), not the pre-8166
`var(--space-md)` residual
- **QuickEntryBox** — wait for cleared input / priority button after
create under shard load (not only `onCreate` mock call)
- **grok process-lifecycle** — prove Symbol.for exit-hook bound with 2
reimports so transform cost stays under 5s on full-suite shards

## Test plan
- [x] Local: FN-8154, QuickEntry clear/priority, process-lifecycle
- [ ] PR merge gate green
- [ ] Post-merge Full Suite on `main` green

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Improved Quick Entry tests to wait for textarea clearing and verify
priority resets to normal after task creation.
* Updated CSS contract assertions for mobile task-detail activity
spacing to match the latest overlay/inset behavior.
* Streamlined the Grok plugin process lifecycle test loop to run fewer
module-evaluation iterations while keeping existing lifecycle and
warning checks.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

plugins/fusion-plugin-grok-runtime/src/__tests__/process-lifecycle.test.ts

@@ -15,10 +15,11 @@ describe("Grok plugin process lifecycle", () => {
   });
 
   /*
-  FNXC:GrokRuntimeTests 2026-07-18-07:15:
-  Bound is proven by a few re-evaluations (Symbol.for exit-hook guard). Full-suite
-  shard load made 15 dynamic imports hit the default 5s testTimeout (transform-heavy
-  plugin graph), not a product hang — keep the assertion, reduce iterations.
+  FNXC:GrokRuntimeTests 2026-07-18-07:25:
+  Symbol.for exit-hook guard is proven by two re-evaluations after the baseline
+  import. Full-suite shard transform load made 5–15 dynamic imports of the full
+  plugin graph hit the default 5s testTimeout; keep the bound assertion, not the
+  iteration marathon.
   */
   it("keeps its process cleanup owner bounded across repeated module evaluation", async () => {
     const baseline = listenerCounts();
@@ -27,7 +28,7 @@ describe("Grok plugin process lifecycle", () => {
     process.on("warning", onWarning);
 
     try {
-      for (let iteration = 0; iteration < 5; iteration += 1) {
+      for (let iteration = 0; iteration < 2; iteration += 1) {
         vi.resetModules();
         await import("../index.js");
       }