Checkpoint F: Relay handoffs

[theDakshJaitly]

Summary

Implements Checkpoint F as a repository-native Relay handoff workflow:

• F0 locks the product contract and real conformance scaffold.
• F1 adds signed portable preview/apply, local drafts, publication, claim, close, schema-v1/v2 reads, and recovery/race guarantees.
• F2 adds the guarded Relay CLI, compact capability discovery, and repository-independent static contract resolver.
• F3 adds the private authenticated Hub API and lazy Relay workbench with strict review dockets, authorization-honest controls, and browser coverage.
• F4 adds deterministic Relay fixtures and release measurements with a mechanically enforced calibration whitelist.

Relay remains: local draft -> published -> acknowledged/claimed -> closed. This PR does not add delivery, notifications, agent spawning, reassignment, admin override, Playbooks, Catch Up, package-root exports, versioning, Graph changes, publishing, or deployment.

Verification

• Independent P0/P1 reviews are clear for F1, F2, F3, F4, and the integrated branch.
• Relay core/CLI/capability/real-lifecycle/release contracts: 102/102 green.
• Final source-resolved Hub contracts/services: 53/53 green.
• Relay UI focused tests: 12/12 green.
• Full Hub Playwright inventory: 45/45 green on the frozen F3 bytes.
• Capability ready envelope: 32,400 / 32,768 bytes.
• Static Relay resolver: about 28.3 KiB / 65,536 bytes.
• Release benchmark contract: 35/35 green.
• No package, root export, version, Graph schema/repair, CI workflow, publishing, or deployment changes.

Release calibration

Pinned Ubuntu 24.04 / Node 22.22.0 characterization run 33249296778 produced strict-valid artifact 9713923132 for exact head 9becb86. Its Relay-only candidates were applied with the frozen formulas:

• Relay assets: 200128 JS / 12285 CSS / 0 font
• Relay draft/list APIs: 5/15 ms small, 3/12 ms medium, 4/13 ms large
• Relay heap: 7753875 / 7754561 / 7748627 bytes

Home, Members, the initial shell, maximum chunk, and every shared runtime budget remain frozen. The final exact head must now pass a separate clean enforcing run with all seven PR checks green before merge.

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