docs(tier2): apply user feedback - 6 workflow conventions

User feedback from the first sandbox run (send_result_to_send_20260616,
2026-06-17) identified 6 conventions Tier 2 must follow. Update the agent
prompt template, slash command template, user guide, and workflow doc:

1. Test runner: ALWAYS use 'uv run python scripts/run_tests_batched.py'
   (NOT 'uv run pytest'). The batched runner provides tier filtering,
   parallelization (xdist), and a summary table that direct pytest lacks.

2. Default branch: this repo uses 'master', not 'main'. The Tier 2 slash
   command now does 'git fetch origin master' (was 'origin main').

3. Line endings: preserve existing. This repo has a mix of CRLF and LF;
   a repo-wide LF standardization is a future track.

4. Throw-away scripts: write to 'scripts/tier2/artifacts/<track>/', NOT
   the base 'scripts/tier2/' directory. The base is reserved for
   production code; throw-away scripts are kept for archival but
   isolated per-track.

5. End-of-track report: write 'docs/reports/TRACK_COMPLETION_<track>.md'
   and update 'state.toml' to 'status=completed'. The user reads this
   to decide merge. Previously this was implicit; now it's explicit.

6. Run-time expectation: tracks are 1-4 hours. If context runs out, Tier
   2 notes progress to disk and continues. The --resume flag picks up
   from the last completed task.

Also updated the user guide with a 'Conventions' section and a
troubleshooting entry for the resume flow. The verify-the-sandbox
checklist now uses 'origin master' instead of 'origin main'.

conductor/workflow.md

@@ -401,6 +401,40 @@ To emulate the 4-Tier MMA Architecture within the standard Conductor extension w
 
 ---
 
+## Tier 2 Autonomous Sandbox (Added 2026-06-16, conventions 2026-06-17)
+
+The Tier 2 autonomous mode is the unattended execution mode for tracks. See `docs/guide_tier2_autonomous.md` for the full user guide. The conventions below are enforced by the Tier 2 agent prompt and slash command template (in `conductor/tier2/agents/tier2-autonomous.md` and `conductor/tier2/commands/tier-2-auto-execute.md`).
+
+### Conventions (MUST follow)
+
+1. **Test runner:** Tier 2 always uses `uv run python scripts/run_tests_batched.py`. NEVER `uv run pytest` directly. The batched runner provides tier-based filtering, parallelization (xdist), and a summary table that direct pytest does not.
+2. **Default branch:** this repo uses `master` (not `main`). When fetching or branching, use `origin/master`. Do not assume `main` exists.
+3. **Line endings:** preserve existing line endings on edit. This repo has a mix of CRLF and LF; repo-wide LF standardization is a future track. For now, do not normalize.
+4. **Throw-away scripts:** Tier 2 writes its working scripts to `scripts/tier2/artifacts/<track-name>/`, NOT the base `scripts/tier2/` directory. The base is reserved for production code (failcount.py, run_track.py, write_report.py, the .ps1 launchers). Throw-away scripts are kept for archival but isolated.
+5. **End-of-track report:** at the end of every track, Tier 2 writes `docs/reports/TRACK_COMPLETION_<track-name>.md` (follow the precedent set by `TRACK_COMPLETION_tier2_autonomous_sandbox_20260616.md`) and updates `conductor/tracks/<track-name>/state.toml` to `status = "completed"`. The user reads this report to decide merge.
+6. **Run-time expectation:** tracks are 1-4 hours. If the model reports it is running out of context, Tier 2 notes progress to disk (the failcount state file) and continues. The user expects autonomous runs to complete without manual "press continue" intervention. The `--resume` flag picks up from the last completed task.
+
+### Hard bans (3-layer enforcement)
+
+| Ban | Layer 1: OpenCode | Layer 2: OS | Layer 3: git hook |
+|---|---|---|---|
+| `git push*` (any push) | `permission.bash` deny rule | n/a | `pre-push` hook refuses all pushes |
+| `git checkout*` (any form) | `permission.bash` deny rule | n/a | `post-checkout` hook logs the checkout |
+| `git restore*` (any form) | `permission.bash` deny rule | n/a | n/a |
+| `git reset*` (any form) | `permission.bash` deny rule | n/a | n/a |
+| File access outside Tier 2 clone + app-data dir | `permission.read`/`write` path allowlist | Windows restricted token + ACLs | n/a |
+
+### Review and merge workflow (user-side)
+
+After Tier 2 finishes a track (success or give-up):
+
+1. In the **main repo** (not the Tier 2 clone), run `pwsh -File scripts/tier2/fetch_tier2_branch.ps1 -TrackName <track-name>` to pull the branch into the main repo as `review/<track-name>`.
+2. Review the diff with Tier 1 (interactive).
+3. On approval, `git merge --no-ff review/<track-name>` (or whatever the user prefers).
+4. Push to origin yourself (the sandbox blocks Tier 2 from pushing).
+
+---
+
 ## Known Pitfalls (2026-06-05)
 
 ### HARD BAN: `git checkout -- <file>`, `git restore`, `git reset` (Added 2026-06-10)