refactor: Route MFE eligibility by manifest (#13592)
## Intent
Remove microfrontend behavior selected by contributor provenance.
## Changes
- Add a canonical package-graph predicate for real package/root scopes
backed by authoritative `package.json` definitions.
- Carry authoritative definition paths into task contexts without
consulting compatibility payloads.
- Route MFE configuration discovery, `get-mfe-port` directory ownership,
and proxy validation through the canonical predicate.
- Preserve deepest-directory and colocated-manifest selection while
excluding pure-native roots, Cargo aggregates, and Cargo members.
- Document the manifest-based MFE eligibility contract.
## Testing
- `cargo test -p turborepo-repository package_graph`
- `cargo test -p turborepo-lib commands::get_mfe_port`
- `cargo test -p turborepo-lib microfrontends`
- `USER=opencode cargo test -p turborepo-task-executor`
- `cargo clippy -p turborepo-repository -p turborepo-lib -p
turborepo-task-executor --all-targets -- -D warnings`
- Pre-push `format` and `check:toml` hooks
Advances TURBO-5798.
