chore: polish for FOL contract delivery (CHANGELOG, CLI guardrails, metadata)

- Update CHANGELOG.md for 1.1.0 (date, refactoring, repository fixes)
- Add overwrite guardrails to imhotep-cli init — skips existing files
- Add bugs/homepage/keywords metadata to 5 public packages
- Mark imhotep-bench and imhotep-fixtures as private packages
- Add selector field to SourceReference interface (core types)
- Remove 7  casts from check-all.ts (folAst.position, cardinality results)
- Generate package-lock.json for reproducible installs

packages/imhotep-fixtures/package.json

@@ -35,5 +35,6 @@
   "dependencies": {
     "imhotep-cdp": "^1.0.0",
     "imhotep-playwright": "^1.0.0"
-  }
+  },
+  "private": true
 }