install pql 1.4.26 changelog-mode hooks

Replaces the legacy pql-plan.json export hooks with the new
changelog-aware set: pre-commit now stages incremental changelog
deltas via 'pql plan export --stage'; post-merge replays new
changelog files into pql.db; post-checkout / post-rewrite rebuild
pql.db when branch state changes. Companion shims under .githooks/
keep core.hooksPath = .githooks the single activation point.

Hook bodies are de-baked — pql 1.4.26 ships them with absolute
paths to the local pql binary, which doesn't survive cross-machine
tracking. Restored 'pql' on PATH form so the tracked copy stays
portable. Filed back-channel for pql to keep portable form.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.pql/hooks/pre-commit

@@ -1,11 +1,8 @@
 #!/bin/sh
 # --- pql plan export ---
-# Auto-installed by pql init. Exports planning state so it's
-# committed alongside code changes. Safe no-op if pql is absent.
-if command -v pql >/dev/null 2>&1; then
-    pql plan export 2>/dev/null
-    if ! git diff --quiet -- .pql/pql-plan.json 2>/dev/null; then
-        git add .pql/pql-plan.json
-    fi
-fi
+# Auto-installed by pql init. Exports planning state and stages the
+# snapshot so it lands in the same commit as the change that produced
+# it. The absolute pql path is baked in at install time — re-run
+# 'pql init' if the binary moves.
+pql plan export --stage 2>/dev/null || true
 # --- end pql ---