Merge worktree-hooks-d-subagent into worktree-hooks-e-protocol

Bring the hook-protocol library branch onto the updated stack (master via A→B→C→D).
No review fix on E (#123 converged clean in its own round). The only conflict was
docs/rfc/README.md: kept D's corrected subagent RFC title (agentType dropped)
alongside E's own hook-protocol RFC index row.

tsconfig.json

@@ -38,6 +38,7 @@
     { "path": "./packages/bash/bash-local" },
     { "path": "./packages/bash/tool-bash" },
     { "path": "./packages/compact/compact" },
+    { "path": "./packages/compact/compact-basic" },
     { "path": "./packages/support/invariants" },
     { "path": "./packages/ui/acp" },
     { "path": "./packages/ui/acp-agent" },