fix(terminal): deadline must cover the body, precache must ignore the cache-bust query

Review fixes. Two of these are defects in the previous commit.

1. The fetch deadline only covered time-to-headers. `await fetch()` settles on
   response headers, so clearing the abort timer in a finally around it left the
   body — the multi-megabyte `?full=1` capture the deadline exists for —
   completely unbounded; it only ever bounded a server that accepts a connection
   and never replies. Measured against a server that sends headers immediately
   and stalls the body 4s under a 1s deadline: fetch resolved at 30ms, timer
   cleared there, body completed at 4026ms unaborted. Now the body is read
   inside `_fetchTerminalCapture`, which returns {json, headers, headersAt} —
   headers because two callers read server-timing, headersAt because those same
   callers measure header-vs-body time and can no longer observe that moment.
   `_terminalCaptureInflight` is scoped the same way, so a body still streaming
   counts toward a capture starting beside it. Same test now aborts at 1005ms.

2. The precache could never be hit, and the previous commit made that expensive
   rather than free. `renderIndexHtml` runs `cacheBustAssets`, which appends
   `?v=<mtime>` to every same-origin .js/.css reference INCLUDING content-hashed
   names — confirmed against a running instance:
   `vendor/xterm-zerolag-input.6fee72f2.js?v=1789402869101`. `caches.match` is
   query-sensitive, so entries keyed on the bare hashed path were unreachable;
   deriving the list from the manifest turned cheap 404s into ~1.3MB downloaded
   at every install that nothing could read back, once per deploy now that
   CACHE_NAME rotates. The fallback match takes `{ ignoreSearch: true }`, which
   also lets runtime-cached entries survive an mtime change.

3. `_wsOutputGapSession` was only cleared in ws.onopen, so paths that already
   repaint the buffer left it set and the socket replayed everything a second
   time. `selectSession` loads the buffer and only THEN calls `_connectWs`, so
   neither the _isLoadingBuffer nor the _terminalRefreshOwner guard applied.
   `_markTerminalBufferReconciled()` is now called from _onSessionNeedsRefresh's
   finally, from selectSession after its load, and from _cleanupSessionData.

   The scope claim was also wrong and is corrected in the comment: when the
   network drops, SSE drops with it and handleInit's keepTerminal branch already
   reconciles. The genuinely uncovered case is the WS dying while SSE stays up,
   where _onSSETerminal discards SSE terminal frames until _wsReady flips in
   onclose — up to the ping+pong window of output nothing writes.

4. CLAUDE.md said "all of them measured rather than reasoned", which the PR's
   own "not verified" section contradicted. Split explicitly: the replay race is
   measured, the watchdog mechanism is verified against xterm 6.0.0 under jsdom
   (field path resolves, a forced stale handle makes refreshRows a no-op, the
   kick schedules a fresh frame), and the iOS rAF-discard premise is reasoned
   and still wants a device. Adds the two missing entries — the WebSocket
   reconcile and the sw.js/build.mjs "keep these in sync or the build throws"
   contract.

Also: test/xterm-private-api.test.ts pins the RESOLVED lockfile version instead
of the declared `^6.0.0` range, which was the wrong assertion in both directions
— a real upgrade to 6.4.0 can rename a private field while resolving inside the
range, and an innocuous range edit failed while changing nothing installed. And
test/sw-precache-manifest.test.ts now parses HASHABLE out of scripts/build.mjs
rather than hand-copying it, which was the same drift this PR exists to fix; the
parse is guarded against silently matching nothing.

The deadline fix has a behavioural test against a real socket plus a source
guard asserting `await res.json()` precedes the finally — verified to fail when
the helper is reverted to the old shape, so it is not vacuous.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/web/public/sw.js

@@ -111,7 +111,17 @@ self.addEventListener('fetch', (event) => {
         }
         return response;
       })
-      .catch(() => caches.match(request))
+      // ignoreSearch, or the precache can never be hit. `renderIndexHtml` runs
+      // `cacheBustAssets`, which appends `?v=<mtime>` to EVERY same-origin
+      // `.js`/`.css` reference — content-hashed names included, so the page asks
+      // for `/app.556be563.js?v=1789423735875` while the precache stored
+      // `/app.556be563.js`. `caches.match` is query-sensitive by default, so
+      // every precached entry was unreachable and only `/`, the icons and the
+      // manifest could ever be served offline.
+      //
+      // It also makes runtime-cached entries survive an mtime change: the same
+      // file re-requested under a new `?v=` still matches the copy already held.
+      .catch(() => caches.match(request, { ignoreSearch: true }))
   );
 });