chore: commit adapters; add context freshness gate to task check

Adapters are now tracked so non-Mac hosts get full agent context after
a plain git pull. task check runs context:sync first and fails on drift
via git status --porcelain over the 5 adapter paths.

.gitignore

@@ -13,15 +13,7 @@ brain/training-data/**/*.jsonl
 # Go
 vendor/
 
-# ── Generated context files (adapter outputs) ──
-# Canonical sources: .context/PROJECT.md + .skills/*/SKILL.md
-# Everything below is disposable — regenerate with: task context:sync
-AGENTS.md
-CLAUDE.md
-.cursorrules
-.aider.conventions.md
 .aider.conf.yml
-.context/system-prompt.txt
 
 # ── Sensitive ──
 .env