Add explicit cross-agent session resume

[Coding-Dev-Tools]

Summary

Adds explicit cross-agent handoff selection: Classic MCP uses resume_from_session_id, and Smart action=start uses session_id as an ended source. The source must match the exact user, workspace, and repository and must be ended; unavailable sources fail closed. Bounded handoff fields include UTC source timestamps without an automatic expiry or freshness claim.

PrimeAgent now forwards the selected source even when a target session is cached, and tool factories stop injecting active target IDs into start calls. Pi and Prime apply target scope defaults on resume starts while ordinary calls retain session inheritance. The age regression uses a fixed epoch. Schemas and portable contract docs remain synchronized. Pi dependencies also pin proxy-addr 2.0.8 for GHSA-jqcg-44mw-7w3h.

Verification

• Full local offline suite: 7,736 passed, 132 platform/optional-dependency skips.
• Session/Smart slice: 122 passed. Prime integration suite: 149 passed, 1 live-only skip; the affected tool/fleet slice passed again after final helper changes.
• Pi typecheck, 23 package tests, pack inspection, and one real MCP integration test passed; both npm audit modes report zero vulnerabilities.
• Ruff, Pyright 1.1.414, commercial manifest, CSP drift, MCP contract, diff checks, and all eight offline evaluation gates passed.

The PR remains a draft for maintainer review.

[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 2026-10-06T15:42:44.043532Z	46fa1bf	Draft marked ready

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