fix(mcp): bound initialize discovery on one parent deadline

[ScriptedAlchemy]

Summary

• MCP initialize and private project routing share one repository-discovery budget instead of an unbounded git walk.
• A cancelled or expired probe is unavailable, not "project not found".

Test plan

• cargo test -p tracedecay --lib mcp::server::routing::tests::cancelled_repository_discovery_is_unavailable_not_absent -- --exact passed, 1 test (cc-23354)

[changeset-bot]

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Latest commit: 20cc517

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-17T16:16:24.083918Z	20cc517	PR opened

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