PR #5811 cmux eligibility QA

What was tested

1. Failing-first targeted tests for the cmux-only environment in:
   • packages/tmux-core/src/tmux-utils.test.ts
   • packages/tmux-core/src/tmux-utils/pane-spawn-runner.test.ts
   • packages/omo-opencode/src/shared/tmux/tmux-utils.test.ts
2. The complete affected tmux, manager, and background-agent suites: 112 files, 1,111 tests.
3. Full repository typecheck and build.
4. Strict TypeScript no-excuse rules on every edited TypeScript file.
5. A production-module driver importing the OpenCode pane-spawn adapter and tmux-core eligibility, command-builder, and close paths with TMUX absent, TMUX_PANE present, and CMUX_SOCKET_PATH present.
6. An isolated OpenCode HTTP server loading this worktree's built plugin, with an SSE probe that observed session.created.

What was observed

• RED: 41 pass, 3 intended failures. The cmux-only predicate returned false and pane spawn stopped before split-window.
• Review round 1 GREEN was rejected because it broadened literal tmux eligibility. c1-green.log and c2-regression.log are marked superseded.
• Review round 2 RED: 25 pass, 3 intended failures against the separate inline pane predicate and real manager path.
• Review round 2 GREEN: 33 targeted pass, then 289 affected-scope pass across 37 files with 662 assertions.
• Review round 3 GREEN: 1,041 affected-scope pass across 108 files with 1,912 assertions.
• Review round 4 GREEN: 1,044 affected-scope pass across 97 files with 2,579 assertions.
• Review round 5 GREEN: 1,111 affected-scope pass across 112 files with 2,720 assertions.
• Typecheck: clean across root, scripts, and all packages.
• Build: completed successfully.
• Strict TypeScript audit: no violations in thirteen edited source/test files.
• Real module surface: eager pane spawn succeeded, then graceful close executed both send-keys C-c and kill-pane.
• Authenticated cmux pane, window, and session surfaces failed closed before either metacharacter credential reached the command runner; neither probe file was created.
• OpenCode surface: local plugin configuration was visible through /config, server health was good, and the event wire delivered session.created.
• Isolation: the real OpenCode database stayed at 21,931 sessions before and after.
• Final post-review rerun loaded the rebuilt plugin on isolated port 45482, created session ses_070da0fd9ffeDC9YLuxO6nPzgy, observed session.created, preserved the same 21,931 real-session count, and removed the server, port listener, and temp directory.
• Release-candidate rerun after round 4 loaded the rebuilt plugin on isolated port 45483, created session ses_070b2a731ffe1xM8M4OFL2v8kI, observed session.created, preserved the same 21,931 real-session count, and removed the server, port listener, and temp directory.

Why it is enough

The RED/GREEN pair proves the exact review blocker changed for the right reason. The final design keeps literal tmux detection unchanged and scopes cmux compatibility to inline pane lifecycle only. The broader suites protect standard tmux, disabled environments, escaping, spawn, activation, replacement, closing, and polling behavior. The background callback test proves producer entry points delegate eligibility instead of stopping before the manager. Security tests prove cmux never receives tmux -e credential arguments. The production-module driver exercises the OpenCode adapter's selected inline pane predicate and uses the same predicate for tmux-core close. Literal tmux-core defaults remain unchanged for unsupported window/session operations. The isolated OpenCode server proves the built local plugin loads and the lifecycle event that reaches TmuxSessionManager.onSessionCreated is present on the real harness wire.

What was omitted

Raw server logs and environment dumps were not copied because they can contain host-specific or authentication-sensitive values. The evidence records only the local plugin path, public health response, generated isolated session ID, event type, counts, and cleanup state.

Cleanup receipt

• Killed isolated OpenCode server session bash_65.
• Confirmed TCP port 45481 has no listener.
• Removed /tmp/omo-pr5811-opencode-qa.
• Removed temporary .local-ignore/lsp-pr-5811 symlink.
• Confirmed the real OpenCode session count remained 21,931.
• Killed final isolated server bash_103, confirmed TCP 45482 was free, and removed /tmp/omo-pr5811-final-qa.
• Confirmed both shell-injection probe paths under /tmp are absent.
• Killed release-candidate server bash_155, confirmed TCP 45483 was free, and removed /tmp/omo-pr5811-release-qa.
• Re-ran native-tmux auth tests under an outer fake-cmux environment; all pass.
• Confirmed session cleanup sends no commands under fake cmux TMUX.