fix(#520): register package-identity.cjs in inventory (regression from #516) (#521)

#516 added get-shit-done/bin/lib/package-identity.cjs without regenerating
the inventory, breaking inventory-manifest-sync and inventory-counts on next.
Regenerate docs/INVENTORY-MANIFEST.json and bump docs/INVENTORY.md
CLI-module count 76 -> 77 with the new row.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

docs/INVENTORY-MANIFEST.json

@@ -1,5 +1,5 @@
 {
-  "generated": "2026-05-29",
+  "generated": "2026-05-30",
   "families": {
     "agents": [
       "gsd-advisor-researcher",
@@ -298,6 +298,7 @@
       "milestone.cjs",
       "model-catalog.cjs",
       "model-profiles.cjs",
+      "package-identity.cjs",
       "phase-command-router.cjs",
       "phase-lifecycle.cjs",
       "phase.cjs",