chore: remove accidentally committed .bak and .chronomemory runtime files

specsmith upgrade --full migration created backup (.bak) files and
.chronomemory/events.wal which were accidentally staged. Removing from
index and adding patterns to .gitignore.

Co-Authored-By: Oz <oz-agent@warp.dev>

Author: tbitcs

.gitignore

@@ -1,39 +1,48 @@
-# Python
-__pycache__/
-*.pyc
-*.pyo
-.eggs/
-*.egg-info/
-dist/
-build/
-.venv/
-.env
-
-# Rust
-firmware/rust/target/
-
-# specsmith runtime
-.specsmith/workitems.json
-.specsmith/runs/
-.specsmith/chat/
-.specsmith/sessions/
-.specsmith/ledger.jsonl
-.specsmith/pids/
-.specsmith/logs/
-.specsmith/credits.json
-.specsmith/model-rate-limits.json
-.chronomemory/*.wal
-.chronomemory/*.tmp
-
-# IDE
-.vscode/settings.json
-.idea/
-*.icloud
-.DS_Store
-
-# Test artifacts
-.pytest_cache/
-htmlcov/
-.coverage
-*.log
-/tmp/
+# Python
+__pycache__/
+*.pyc
+*.pyo
+.eggs/
+*.egg-info/
+dist/
+build/
+.venv/
+.env
+
+# Rust
+firmware/rust/target/
+
+# specsmith runtime
+.specsmith/workitems.json
+.specsmith/runs/
+.specsmith/chat/
+.specsmith/sessions/
+.specsmith/ledger.jsonl
+.specsmith/pids/
+.specsmith/logs/
+.specsmith/credits.json
+.specsmith/model-rate-limits.json
+.chronomemory/*.wal
+.chronomemory/*.tmp
+
+# IDE
+.vscode/settings.json
+.idea/
+*.icloud
+.DS_Store
+
+# Test artifacts
+.pytest_cache/
+htmlcov/
+.coverage
+*.log
+/tmp/
+
+# specsmith migration backups — regeneratable, never commit
+*.bak
+.specsmith/*.bak
+docs/governance/*.bak
+docs/*.bak
+
+# ChronoMemory ESDB runtime files — regenerated automatically
+.chronomemory/