Address second round of PR review feedback

- Replace getConfig<T> with getMetadata/setMetadata on CliAuth, removing
  the unsafe type parameter in favor of returning unknown
- Move updateInstanceConfig from cli-module-auth public API to
  CliAuth.setMetadata, removing the cross-package dependency
- Rename 'config' to 'metadata' in StoredInstance and storage schemas
- Add zod validation at consumer sites (cli-module-actions) for
  type-safe metadata access
- Fix zod imports to use zod/v3 for compatibility with zod v4
- Add proper-lockfile to cli-node for metadata write locking
- Refactor cli-node storage from fs-extra to node:fs
- Remove @backstage/cli-module-auth dependency from cli-module-actions

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

yarn.lock

@@ -2828,10 +2828,10 @@ __metadata:
   dependencies:
     "@backstage/backend-test-utils": "workspace:^"
     "@backstage/cli": "workspace:^"
-    "@backstage/cli-module-auth": "workspace:^"
     "@backstage/cli-node": "workspace:^"
     "@backstage/errors": "workspace:^"
     cleye: "npm:^2.3.0"
+    zod: "npm:^3.25.76 || ^4.0.0"
   bin:
     cli-module-actions: bin/backstage-cli-module-actions
   languageName: unknown
@@ -3154,6 +3154,7 @@ __metadata:
     "@backstage/test-utils": "workspace:^"
     "@backstage/types": "workspace:^"
     "@manypkg/get-packages": "npm:^1.1.3"
+    "@types/proper-lockfile": "npm:^4"
     "@types/yarnpkg__lockfile": "npm:^1.1.4"
     "@yarnpkg/lockfile": "npm:^1.1.0"
     "@yarnpkg/parsers": "npm:^3.0.0"
@@ -3162,6 +3163,7 @@ __metadata:
     fs-extra: "npm:^11.2.0"
     keytar: "npm:^7.9.0"
     pirates: "npm:^4.0.6"
+    proper-lockfile: "npm:^4.1.2"
     semver: "npm:^7.5.3"
     yaml: "npm:^2.0.0"
     zod: "npm:^3.25.76 || ^4.0.0"