Summary

Adds a fail-closed workspace package boundary gate.

The gate derives workspace package facts at runtime from
scripts/publish-manifest.json, the workspace package.json files, their
private flags, and the workspace roots. It does not add a public
package-classification manifest or a public schema.

Scope

• No wire / schema-runtime / signing / CLI / runtime change.
• No new published package.
• No public protocol schema; no committed package census.
• Published packages must match scripts/publish-manifest.json.
• Non-published workspace packages must remain private: true.
• apps/ and examples/ packages are never published and stay private.
• Every package must sit under a recognized workspace root (fail closed).
• Existing internal-package invisibility rules remain unchanged.

Verify

pnpm vitest run tests/tooling/workspace-package-boundary.test.ts
pnpm vitest run tests/tooling/internal-package-invisibility.test.ts tests/tooling/workspace-package-boundary.test.ts
pnpm vitest run tests/tooling/
pnpm format:check
bash scripts/ci/forbid-strings.sh
git diff --check

The second commit adds .gstack/ to .prettierignore so the repo-wide
format:check does not scan gitignored local generated tooling state.