chore(meta): narrow .pql gitignore to track changelog (pql migration phase 0)

The blanket `.pql/` ignore would have hidden `.pql/changelog/` — pql's durable,
git-versioned planning state — making the whole migration's output invisible to
git. Narrow to ignore only the rebuildable DBs (index/pql .db + WAL/SHM) and
track config.yaml + changelog/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -83,4 +83,9 @@ wiki/economics/corporations/generated_corporations.toml
 
 # Local agent tooling caches (per-machine, not shared)
 .clide/
-.pql/
+
+# pql: ignore the rebuildable local databases (index + planning DB + WAL/SHM
+# sidecars), but TRACK .pql/config.yaml and .pql/changelog/ — the changelog is
+# pql's durable, git-versioned planning state (LWW, idempotent replay).
+.pql/*.db
+.pql/*.db-*