tracking(storage): complete managed dependencies

[Phoenix500526]

Problem

ManagedDependencyEnvironmentAuthority landed in #2485, but it remains a
stacked foundation without a production consumer. The producer boundary,
bundled runtime supply chain, and owner/worker composition are documented but
have no focused tracker, so M1.3 can remain indefinitely incomplete.

#4174 removed the dormant Git-executable managed-workspace path. The follow-up
must compose with the current Gitoxide direction rather than restore that path.

Completed baseline

• Canonical dependency identity, exclusive storage-root ownership, immutable artifact publication, external SQLite receipts, leases, pending reservations, GC, crash convergence, and tamper/ADS/reparse checks are implemented by feat(storage): add managed dependency artifact authority #2485.
• The storage authority is intentionally fail-closed and still has no production owner or consumer.

Remaining work

• Add a producer boundary that proves the process tree exited before provision() resolves, with quota, cancellation, timeout, and real npm .bin symlink coverage
• Add the bundled npm runtime supply chain and hermetic network policy, including manifest, audit, license/SBOM material, packaging, and packaged-runtime smoke
• Bind an admitted Gitoxide workspace baseline to an owner-scoped dependency lease and expose only read-only Read/Glob/Grep access
• Compose the lifecycle through Desktop, CLI, and Runtime Host, including drain/close ordering and execution-scope revalidation
• Keep the storage build, focused authority/crash suites, and real Windows ADS gate green

Non-goals

• Shell/Build execution, dependency mutation, secrets, or scratch access
• Automatically enabling managed mode for existing users
• Restoring the retired Git CLI owner or weakening fail-closed rules

Design

• Managed Dependency Storage Authority v1
• Baseline implementation: feat(storage): add managed dependency artifact authority #2485
• Retired dormant path: refactor: remove dormant Git workspace write path #4174