fix(mcp): close late probe sessions

[sethkarten]

Summary

• Close an injected MCP session even when transport open resolves after the probe deadline.
• Use independently bounded cleanup and report only redacted late-cleanup failures.
• Keep public MCP commands declarative; probing remains an injected boundary capability.

Validation

• Biome scoped check passed for the five changed source/test files.
• Scoped MCP probe test passed: 9 tests.
• git diff --check passed.

Not run: root tsgo --noEmit is unavailable in this checkout. The scoped public/declaration suites cannot load because workspace dependencies are absent.

Note

Fix MCP probe to close sessions that resolve after the deadline

• Implements runMcpDeclarationProbe in mcp-probe.ts with injected transport, enforcing trust/offline guards, bounded timeouts, and guaranteed session cleanup.
• Sessions that open after the deadline has elapsed are closed asynchronously; failures during late cleanup are reported via an onLateCleanupFailure callback rather than thrown.
• All errors are redacted to generic public messages via publicProbeError to avoid leaking endpoint or transport details.
• Removes mcp test from the public CLI command, throwing immediately if invoked in that context.

^{Macroscope summarized fb70146.}

Final reconciled validation

• Head: 4af99680b698918cd14981d506fcd14804cc1f81
• Core-08 reconciled with final Core-07 parent; injected-only probe boundary preserves late-open eventual cleanup while the public command stays unavailable.
• Non-writing Biome over the full Core-05–Core-09 changed-path union: pass (29 files)
• Root tsgo --noEmit: pass
• Configured MCP, lifecycle, catalog, and registry regressions: 16 files, 293/293 tests pass under sanitized RLM_/PRIME_AGENT_ environment
• git diff --check: pass; final worktree clean

---

Note

Medium Risk
Changes MCP trust/error-handling boundaries and session lifecycle; scope is limited to probe plumbing and CLI surface, with redaction and tests.

Overview
Adds runMcpDeclarationProbe as an internal, injected-transport handshake (initialize then tools/list) with bounded timeouts, generic error messages (no URL/credential leakage), and cleanup of sessions that open after the deadline via onLateCleanupFailure.

Public CLI no longer documents or accepts mcp test; it fails before MCP parsing or settings access. Help text for mcp is updated to match declarative-only commands.

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[sethkarten]

Superseded by #1338 as part of the physical Core/MCP stack split. The replacement preserves this PR’s reviewed semantic delta on the corrected shared #1243 foundation. Closing this PR to avoid duplicate review; branch retained for provenance.