Content-script / port recovery after long Draft.js hangs without full Chrome restart

[Trace824]

Summary

After Draft.js compose wedges (long hangs), navigate / read_page can time out (~30s) with content-script port disconnect / reinject loops. Operators should not need a full Chrome restart to restore messaging.

Repro

• Context: Tab stuck after heavy compose / selector timeouts on x.com.
• Steps:
  1. Trigger prolonged Draft.js hang (selector type without fast-path, or repeated failed inserts).
  2. Call navigate or read_page.
• Observed: ~30s timeouts; port disconnect; reinject attempts; sometimes only full Chrome restart restores health.

Code pointers (verified against /workspace/FSB)

• extension/content/lifecycle.js — chrome.runtime.connect({ name: 'content-script' }), port disconnect handling (~L546–553).
• extension/background.js — port_disconnected (~L5335); ensureContentScriptInjected / script_reinjection recovery (~L5559–5569, ~L16888).
• extension/content/messaging.js — tool timeout / Unknown tool paths.

Proposed fix

Harden recovery: on port disconnect after compose stress, single-flight reinject + bounded retry for navigate/read_page without requiring browser restart. Ensure hung draft_fast_path / readiness waits cannot leave the port permanently wedged (timeouts cancel outstanding work).

Acceptance / regression

• After induced hang, navigate/read succeed within one reinject cycle.
• No restart required for recovery in the common case.

Owner

extension

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Priority: P1 · Owner: extension