fix(placement): remove subagent model allowlist, prefer loaded then host default

[androidand]

Summary

• A subagent delegated to a host with a model already loaded got evicted for a different model — local_subagent_placement_models acted as an eligibility filter that ran before the "prefer already loaded" scoring bonus could ever apply.
• Removed the allowlist entirely: hand-curated, undiscoverable (no docs, no CLI, no warning on silent eviction), and for a self-curated local fleet the failure it guarded against (a model flubbing tool-call JSON) is a one-time visible bad turn, not silent corruption.
• New priority in bestModel(): loaded model > host's own configured default model (GET /api/config/info, already exposed by llama-skein but never consulted here) > parent's own model > plain fit/speed scoring.
• Also includes a small unrelated fork-manifest fix: registers lifecycle-inject.test.ts (added in fix(peer): resolve InstanceRef before any session-scoped call in sidecar delivery #93) as an owned fork file — fork:verify only catches a missing registration pre-push, so it slipped through on the last PR.

Test plan

• placement.test.ts updated/extended: residency beats an allowlisted-cold model, host default beats plain fit/speed, host default beats parent's model, residency still beats host default.
• bun test test/local/ — 320 pass (1 unrelated pre-existing failure confirmed present on unmodified code too — stale hostname fixture).
• bun turbo typecheck — 30/30 clean.
• bun run fork:verify — 0 unregistered divergence.

🤖 Generated with Claude Code

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