Harden Defty project target resolution

[Maneek21]

Summary

• add one org-scoped active-project resolver shared by Defty and human MCP tools
• recover a complete canonical project name from planner prose without accepting partial token guesses
• fail closed for ambiguous, missing, archived, deleted, or multiply-linked targets
• add regression coverage for the original Route + Packing contamination and sibling-project ambiguity
• harden the production image by removing unused npm and pinning the runtime to pnpm 10.34.5 with patched node-tar

Verification

• pnpm --filter @deft/api typecheck
• pnpm --filter @deft/api exec tsx --test test/resolve-project-target.test.ts test/agent-reply-discussion-command.test.ts (30 passed)
• fresh Postgres bootstrap (db:push-full split into schema push + extras)
• oauth-mcp.test.ts (10 passed)
• mcp-write-tools.test.ts plus Defty/resolver coverage (53 passed)
• browser replay: approval created OPS-9 in Route + Packing Reliability, assigned to Tomás, P2, no due date
• production Docker image build and runtime binary smoke
• Trivy 0.70.0 production-image scan: 0 critical vulnerabilities