fix(test): exorcise the sidebar-agent ghost from the test suite

browse/src/sidebar-agent.ts was deleted in the v1.14 sidebar refactor, but the
test suite kept testing it for 48 versions. Nothing noticed because the free
suite runs in no CI job and Bun-era module-load errors were suppressed in the
Windows shard runner via an exclusion pattern whose own comment documented the
breakage ('broken on every platform since v1.14 ... exit 0').

- Delete sidebar-security.test.ts + security-source-contracts.test.ts: crashed
  at module load (unguarded readFileSync of the deleted file); per-assertion
  triage confirmed every SERVER_SRC pin targeted the deleted chat prompt
  builder (zero hits in today's server.ts) — nothing to port.
- Delete sidebar-integration.test.ts: 11 of 13 tests exercised deleted
  endpoints (/sidebar-command queue, /sidebar-agent/event, chat buffer); the 2
  passing tests pinned only the blanket auth gate, covered by
  server-auth.test.ts + dual-listener.test.ts.
- Delete test/skill-e2e-sidebar.test.ts: E2E for the deleted queue flow.
- sidebar-ux.test.ts 1,669 -> 830 lines: 20 dead-chat describes + 15 dead
  tests removed (incl. 10 vacuous passes asserting on empty indexOf slices);
  2 stale pins on LIVE features fixed (content.js typed-catch CSSOM fallback,
  arrow-hint window widened). 95 pass / 0 fail.
- sidebar-tabs.test.ts: both failures were stale pins, not regressions —
  forceRestart's deliberate ws.close(4001) and the terminal-agent spawn that
  moved into spawnTerminalAgent() (identity-based kill refactor). 28 pass.
- touchfiles.ts: drop the three sidebar E2E entries from BOTH maps
  (E2E_TOUCHFILES + E2E_TIERS) — they pointed diff-selection at the deleted
  file, so those tests were unreachable by any diff.
- test-free-shards.ts: remove the now-dead sidebar-agent exclusion pattern.

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

browse/test/sidebar-tabs.test.ts

@@ -157,7 +157,9 @@ describe('sidepanel-terminal.js: eager auto-connect + injection API', () => {
   test('forceRestart helper closes ws, disposes xterm, returns to IDLE', () => {
     expect(TERM_JS).toContain('function forceRestart');
     const fn = TERM_JS.slice(TERM_JS.indexOf('function forceRestart'));
-    expect(fn).toContain('ws && ws.close()');
+    // Deliberate close code so the agent's close handler can distinguish an
+    // intentional restart from a dropped connection (codex D8 redesign).
+    expect(fn).toContain("ws.close(4001, 'intentional-restart')");
     expect(fn).toContain('term.dispose()');
     expect(fn).toContain('STATE.IDLE');
     expect(fn).toContain('tryAutoConnect()');
@@ -222,8 +224,16 @@ describe('cli.ts: sidebar-agent is no longer spawned', () => {
   });
 
   test('Terminal-agent spawn survives', () => {
-    expect(CLI_SRC).toContain('terminal-agent.ts');
-    expect(CLI_SRC).toMatch(/Bun\.spawn\(\['bun',\s*'run',\s*termAgentScript\]/);
+    // The inline Bun.spawn of termAgentScript moved into the shared
+    // spawnTerminalAgent helper (terminal-agent-control.ts) so the CLI
+    // cold-start path and the supervisor respawn path share one
+    // identity-tracked spawn. The CLI must still call it.
+    expect(CLI_SRC).toContain("import { spawnTerminalAgent } from './terminal-agent-control'");
+    expect(CLI_SRC).toMatch(/spawnTerminalAgent\(\{/);
+    const CONTROL_SRC = fs.readFileSync(
+      path.join(import.meta.dir, '../src/terminal-agent-control.ts'), 'utf-8');
+    expect(CONTROL_SRC).toContain('terminal-agent.ts');
+    expect(CONTROL_SRC).toMatch(/spawn\(\['bun',\s*'run',\s*script\]/);
   });
 });