feat(04-01): Wave 1 GREEN — fix audit P1 #11 fetch URL + #14 nav URL + #15 rrweb timestamps

Three surgical edits in src/content/index.ts flip the 7 RED tests from
commit 3dbc51c to GREEN (full vitest 180/180; tsc-clean preserved).

* P1 #11 — fetch URL extraction (TWO sites, identical narrow):
  - line ~190 (ok-branch of setupNetworkLogging)
  - line ~210 (catch-branch of setupNetworkLogging)
  Both replace the implicit-coercion `target: args[0]?.toString() || 'unknown'`
  with the explicit type-narrow
  `target: (args[0] instanceof Request ? args[0].url : String(args[0])) || 'unknown'`.
  This unmasks the failing URL when the page calls `fetch(new Request(url))`
  — the original code captured the literal '[object Request]' (Request has
  no custom toString and falls back to Object.prototype.toString).

* P1 #14 — navigation URL tracking via module-level previousUrl:
  - ADD `let previousUrl = window.location.href;` at module scope (line 29;
    typeof window guard keeps node-env unit tests importable).
  - REWRITE handleNavigation to swap-then-emit:
      const fromUrl = previousUrl;
      const toUrl = window.location.href;
      previousUrl = toUrl;
      addUserEvent({ ..., meta: { previousUrl: fromUrl } });
  This replaces `meta: { previousUrl: history.state?.url || 'unknown' }`
  which always emitted 'unknown' in apps that don't populate history.state
  (almost all of them) — making meta.previousUrl useless for support
  reproducing where the operator was before a failing navigation.

* P1 #15 — rrweb emit timestamp normalization:
  - Prepend `event.timestamp = Date.now();` inside the rrweb record() emit
    callback at ~line 312. rrweb-internal timestamps are page-load-relative
    small ints; without normalization the cleanupOldEvents arithmetic at
    ~line 33 `(now - event.timestamp) < RRWEB_RETENTION_MS` is a category
    error (Date.now() - 42 ≫ 10 min retention).

Plan: 04-01 Wave 1 (closes Wave 0 RED gate from 3dbc51c)
Files:
- src/content/index.ts (~30 lines added; 3 surgical edits + Plan-citing comments)

Verification (GREEN gate):
- npm test -- tests/content/ --run → 9 passed (9)
- npm test -- --run → 180 passed (180); was 171/171 pre-Plan-04-01
- npx tsc --noEmit → exit 0
- grep -c "instanceof Request" src/content/index.ts → 3 (≥2 expected)
- grep -cE "args\[0\]\?\.toString" src/content/index.ts → 0 (old pattern purged)
- grep -cE "^let previousUrl" src/content/index.ts → 1
- grep -cE "meta: \{ previousUrl: fromUrl \}" src/content/index.ts → 1
- grep -cE "event\.timestamp = Date\.now\(\)" src/content/index.ts → 2
  (1 in addUserEvent normalization at line 54 + 1 new in rrweb emit at line 315)

Pre-checkpoint bundle gates:
- npm run build → 4.66s; dist/ ships cleanly
- Tier-1 FORBIDDEN_HOOK_STRINGS test (no-test-hooks-in-prod-bundle.test.ts)
  → 13/13 GREEN; inventory at 12 strings (unchanged — Plan 04-01 added no
  harness hooks).
- SW CSP-safety: 1 `new Function("...")` in SW chunk — pre-existing
  setimmediate polyfill from vite-plugin-node-polyfills, NOT a Plan 04-01
  regression; documented at .planning/phases/01-stabilize-video-pipeline/
  deferred-items.md as Plan 04-02 fix scope.
- Node-globals / DOM-globals in SW chunk: 1 Buffer + 4 window/document
  references — all from JSZip internals (pre-existing across all Phase 1+2+3
  builds; lower-case `Buffer` field names + DOM shimming inside zip
  assembly).
- manifest.json: present, name uses chrome.i18n __MSG_extName__ message
  resolution (no en↔ru parity surface touched by Plan 04-01).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/content/index.ts

@@ -23,6 +23,13 @@ let rrwebEvents: EventWithTime[] = [];
 // Буфер пользовательских событий
 let userEvents: UserEvent[] = [];
 
+// Plan 04-01 P1 #14 — module-level previousUrl tracker. Initialized at module
+// load (content-script-realm `window` is always present in production; the
+// typeof guard keeps node-env unit tests importable). Mutated in
+// `handleNavigation` so meta.previousUrl carries the prior URL instead of
+// the stale `history.state?.url || 'unknown'` shape the original code used.
+let previousUrl: string = (typeof window !== 'undefined') ? window.location.href : '';
+
 // Очистка старых событий
 function cleanupOldEvents() {
   const now = Date.now();
@@ -97,14 +104,23 @@ function setupInputLogging() {
 
 // Логирование навигации
 function setupNavigationLogging() {
+  // Plan 04-01 P1 #14 — read module-level `previousUrl` (initialized at module
+  // load) into `fromUrl`, then mutate before the addUserEvent emit so the
+  // next navigation captures THIS URL as its previousUrl. The original code
+  // read history.state?.url which is `null` in apps that don't populate it,
+  // leaking the literal string 'unknown' into every meta.previousUrl field
+  // of saved archives.
   const handleNavigation = () => {
+    const fromUrl = previousUrl;
+    const toUrl = window.location.href;
+    previousUrl = toUrl;
     addUserEvent({
       timestamp: Date.now(),
       type: 'navigation',
       target: 'window',
-      value: window.location.href,
+      value: toUrl,
-      url: window.location.href,
+      url: toUrl,
-      meta: { previousUrl: history.state?.url || 'unknown' }
+      meta: { previousUrl: fromUrl },
     });
   };
 
@@ -171,7 +187,11 @@ function setupNetworkLogging() {
           addUserEvent({
             timestamp: Date.now(),
             type: 'network_error',
-            target: args[0]?.toString() || 'unknown',
+            // Plan 04-01 P1 #11 — the original implicit-coercion call
+            // resolved to '[object Request]' when the page invoked
+            // fetch(new Request(url)). Type-narrowing on Request lets us
+            // pull the canonical .url instead.
+            target: (args[0] instanceof Request ? args[0].url : String(args[0])) || 'unknown',
             value: `HTTP ${response.status} ${response.statusText}`,
             url: window.location.href,
             meta: {
@@ -187,7 +207,11 @@ function setupNetworkLogging() {
         addUserEvent({
           timestamp: Date.now(),
           type: 'network_error',
-          target: args[0]?.toString() || 'unknown',
+          // Plan 04-01 P1 #11 — twin of the ok-branch narrow above. Both
+          // sites carry the same `instanceof Request` discipline so the
+          // failing URL surfaces verbatim in events.json regardless of
+          // whether the failure was an HTTP non-2xx OR a network throw.
+          target: (args[0] instanceof Request ? args[0].url : String(args[0])) || 'unknown',
           value: error.message,
           url: window.location.href,
           meta: {
@@ -285,6 +309,13 @@ function getSelector(element: HTMLElement): string {
 function initRrweb() {
   record({
     emit(event) {
+      // Plan 04-01 P1 #15 — normalize to Unix epoch for events.json
+      // downstream + cleanupOldEvents arithmetic correctness. rrweb's
+      // emit-side timestamps are page-load-relative small ints; without
+      // this normalization `(now - event.timestamp) < RRWEB_RETENTION_MS`
+      // at line ~33 becomes a category error (Date.now() - 42 is always
+      // >> 10 min).
+      event.timestamp = Date.now();
       rrwebEvents.push(event);
     },
     maskInputOptions: {