feat(agent): add opt-in read-only MCP bridge

[DavidHLP]

What changed

Adds an optional local stdio MCP server exposing only the existing authenticated get_my_submissions read tool, plus a request-scoped MCP Client path in the Agent. The default direct path remains unchanged. Tool discovery, parameter bounds, output projection, and fixed error labels preserve the existing Java authorization boundary.

This is stacked on PR #231 (agent/first-delivery at 01637534fb575779ee9be9f289965f35ec43d3b8) and implements the code portions of optional DAV-32/M18 and DAV-33/M19.

Verification

• Locked SDK: mcp==2.3.0; negotiated protocol: 2026-07-28.
• Full Agent suite at the corrected branch tree: 1,676 passed, 1 skipped because optional qdrant_client is not installed.
• Repository-corpus digest regression: 11 passed.
• Local stdio subprocess with an HTTP stub, controlled discovery/call, Agent result backfill, and error/timeout/cancellation regressions passed.
• Standards and specification reviews approved.
• No live UltiCode stack or model provider was used. Personal hours and independent learning evidence remain unrecorded; these optional extensions do not gate U02/U03 formal acceptance.

[DavidHLP]

Cross-system status — 2026-10-12 02:39 UTC

This optional PR remains Open/Draft at 7e44463a01c68d77ce27b8220f8631745156ad5b. Its local tests do not constitute live-service or whole-project acceptance. The current PR check readback contains only a successful GitGuardian check; no current Actions result or approving review is recorded. The project is not ready for full manual acceptance; see the current Notion project snapshot.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-12T04:08:59.661221Z	8d27a31	New commits

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 8d27a31537

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[chatgpt-codex-connector]

Keep access tokens in HttpOnly cookies

In the documented standalone stdio configuration, this reads the user's bearer access token from an environment variable, requiring it to be copied out of its HttpOnly cookie and exposing it to process-environment readers and inherited child processes. That bypasses the repository's explicit token-storage boundary; authenticate the standalone bridge through a host-mediated cookie/session channel rather than provisioning the raw token in ULTICODE_AGENT_ACCESS_TOKEN.

AGENTS.md reference: AGENTS.md:L55-L56

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