feat(agent): add agent-native wiki protocol surfaces

[changeroa]

Summary

• add content-addressed StableRef, VersionID, immutable manifest, epistemic governance, capability, receipt, Task/Run/effect, and reconciliation contracts
• add one 14-operation registry with six read-only operations and eight governed internal reducers
• expose sg discover/resolve/claims/context/ops plus a registry-derived read-only MCP surface and sg://object resources
• add A2A and AG-UI projections, deterministic retrieval, and receipt-backed governed learning
• add closed Draft 2020-12 schemas, executable conformance receipts, adversarial tests, and CI coverage

Integrity boundaries

• empty capability scopes deny by default
• external effects without durable connector receipts remain UNCERTAIN
• learning promotion rejects forged, stale, wrong-kind, wrong-link, or non-independent records
• MCP derives exposure from read_only registry metadata and never exposes registered mutation operations
• component-state browser evidence was recaptured because package.json and package-lock.json are governed capture sources

Verification

• npm run test:agent-native
• npm test
• npm run build
• npm run validate
• npm run test:consumer-conformance: 147 passed
• npm run test:component-state
• real Chromium component-state capture: 10 passed, 40 artifacts, 2 profiles
• CLI↔MCP conformance: 8/8
• governed learning integrity: 14/14
• closed schema validation: 65/65
• independent final gate: APPROVE

All commands passed on an isolated clean commit whose product tree was byte-identical to this branch.