fix(security): delete dead exports the ripped chat path left behind

Three-way split by importer class:

(a) Zero importers, deleted: the whole attack-attempt logging cluster in
security.ts (logAttempt, AttemptRecord, salted hashPayload + device-salt,
attempts.jsonl rotation, telemetry spawn plumbing incl.
buildTelemetrySpawnCommand/resolveBashBinary — the LIVE attempts.jsonl writer
is tunnel-denial-log.ts with its own rotation); the decision-file handshake
(writeDecision/readDecision/clearDecision/excerptForReview — written for
sidebar-agent's poll loop, which no longer exists); sidebar-utils.ts (whole
module — its sanitizeExtensionUrl 'sanitized before embedding in a prompt'
for the deleted prompt builder); 8 dead server.ts imports (sanitizeExtensionUrl,
generateCanary, injectCanary, writeDecision, rotateRoot, serializeRegistry,
restoreRegistry, clearAgentRecord); buildPtyClearCookie + buildSseClearCookie;
WEBDRIVER_MASK_SCRIPT (orphaned by the D7 stealth narrowing — applyStealth
never used it).

(b) Dead-pin tests edited with their exports: the 'still exported' pin in
stealth-layer-c, the string-content describe in stealth-webdriver (its live
applyStealth behavioral coverage untouched), the clear-cookie assertions,
security-review-flow.test.ts deleted whole (all 4 describes exercised the
dead decision mechanism, incl. a 'simulated sidebar-agent poll loop').

(c) KEPT deliberately: leaseCount (live behavioral coverage),
extractPtyCookie + validatePtySessionToken (extractPtyCookie is adopted by
the terminal-agent cookie-parse unification later in this wave),
resetSessionMarker + clearContentFilters (test-support API for the live
content-security layer).

Also fixes two pre-existing red pins found while here, invisible until the
free suite got a CI job: the v1.44 spawnClaude->maybeSpawnPty rename in
terminal-agent.test.ts, and a cross-file test-isolation bug where
content-security.test.ts's clearContentFilters() wiped the auto-registered
url-blocklist filter for every later file in the same bun process
(security-integration.test.ts failed on co-run; afterAll now restores it).

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

browse/test/content-security.test.ts

@@ -124,6 +124,16 @@ describe('Content filter hooks', () => {
     clearContentFilters();
   });
 
+  // clearContentFilters() wipes MODULE state shared across every test file in
+  // the same bun process — without restoring the built-in registration,
+  // security-integration.test.ts (which asserts the auto-registered blocklist
+  // pipeline) fails whenever the two files co-run. Pre-existing co-run bug,
+  // invisible until the free suite got a CI job.
+  afterAll(() => {
+    clearContentFilters();
+    registerContentFilter(urlBlocklistFilter);
+  });
+
   test('URL blocklist detects requestbin', () => {
     const result = urlBlocklistFilter('', 'https://requestbin.com/r/abc', 'text');
     expect(result.safe).toBe(false);