Fix DMC lifecycle finalizer configuration

[chubes4]

Summary

• keep the DMC provider command map limited to provider operations
• configure finalization through Homeboy's generic settings.worktree_provider_lifecycle.dmc.finalize contract
• verify the lifecycle setting survives config readback
• exercise successful and failed owner outcomes through the separately configured finalizer

Closes #505.

Verification

• bash tests/homeboy-dmc-provider.sh
• git diff --check
• bash tests/verify.sh has the same two pre-existing healthy-fixture assertions failing on untouched origin/main

AI assistance

GPT-5.6 Sol via OpenCode diagnosed the runtime/schema mismatch, implemented the scoped configuration repair, and ran the focused and baseline verification.