## Implementation Plan: Remove Void-World Preamble from AI Gateway

### Goal
Merge the existing fix branch that adds preamble filtering logic, resolving all conflicts and pre-existing failures so that tests pass and lint is clean.

### Steps

1. **Resolve merge conflicts** in these files (all unrelated to the preamble change):  
   - `devplacepy/config.py`  
   - `devplacepy/docs_devrant.py`  
   - `devplacepy/models.py`  
   - `devplacepy/services/devii/actions/catalog/comments.py`  
   - `devplacepy/templates/_comment_form.html`  
   For each, accept the correct version (usually master’s side unless the branch introduced an intentional change). Verify no semantic changes are lost.

2. **Verify the preamble filter code** – ensure the file `devplacepy/services/openai_gateway/system_message.py` contains:  
   - The `PREAMBLE_PROHIBITED_PATTERNS` list with the 7 void-world patterns.  
   - The logic in `apply_system_directives()` that discards the preamble when any pattern matches.  
   - A warning log line.  

3. **Fix the unrelated test failure** in `tests/unit/content.py::test_owns_instance_true_for_creator`.  
   - Inspect `devplacepy/content.py:83-93` (`owns_instance`). The test expects `False` for a creator but gets `True`. This is likely a regression from an earlier merge.  
   - Correct the logic or the test (prefer fixing the implementation to match the intended behavior). After fix, run only this test to confirm it passes.

4. **Run lint with auto-fix** and then re-check:  
   ```bash
   pip install -q ruff
   ruff check --fix .
   ruff check .
   ```  
   Ensure zero new violations reported. (If existing violations are unfixable, verify they are pre-existing and note them as not introduced by this change; but the plan must aim for clean output.)

5. **Run unit tests** – execute `make test-unit` (which runs `pip install -e '.[dev] -q && make test-unit` under the hood). Confirm all tests pass, especially the seven new tests in `tests/unit/services/openai_gateway/system_message_test.py`.

6. **Final verification** – manually inspect that `devplacepy/services/openai_gateway/CLAUDE.md` line 49 still documents the prohibited preamble feature. No further changes needed.

### Definition of Done

All checks below must pass:

- [ ] Merge conflicts resolved; no merge markers remain in any file.
- [ ] `devplacepy/services/openai_gateway/system_message.py` exists and contains the preamble filtering logic with all 7 prohibited patterns.
- [ ] `tests/unit/services/openai_gateway/system_message_test.py` exists and contains the 7 test cases (including the parametrized pattern test).
- [ ] The previously failing test `tests/unit/content.py::test_owns_instance_true_for_creator` now passes.
- [ ] `ruff check .` exits with code 0 (no new violations introduced).
- [ ] `make test-unit` exits with code 0 and all tests pass.
- [ ] Documentation in `devplacepy/services/openai_gateway/CLAUDE.md` still references the prohibited preamble feature.