fix(hooks): remove all venv auto-repair code that deleted .venv directories

BREAKING: Removes automatic venv management that was causing session failures

Changes:
- Delete scripts/venv-repair.sh (was deleting and recreating venvs)
- Remove auto-repair code from projman/hooks/startup-check.sh
- Remove venv-repair call from scripts/post-update.sh
- Remove rm -rf .venv instructions from docs/UPDATING.md and CONFIGURATION.md
- Update docs/CANONICAL-PATHS.md to remove venv-repair.sh reference

Additionally:
- Add Pre-Change Protocol to CLAUDE.md (mandatory dependency check before edits)
- Add Pre-Change Protocol enforcement to claude-config-maintainer plugin
- Add Development Context section to CLAUDE.md clarifying which plugins are
  used in this project vs only being developed
- Reorganize commands table to separate relevant vs non-relevant commands

The venv auto-repair was the root cause of repeated MCP server failures,
requiring manual setup.sh runs after every session start.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/UPDATING.md

@@ -132,10 +132,8 @@ When updating, review if changes affect the setup workflow:
 ### Dependencies fail to install
 
 ```bash
-# Rebuild virtual environment
+# Install missing dependencies (do NOT delete .venv)
 cd mcp-servers/gitea
-rm -rf .venv
-python3 -m venv .venv
 source .venv/bin/activate
 pip install -r requirements.txt
 deactivate