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.build.json

@@ -23,6 +23,7 @@
     { "path": "./packages/core/agent-core" },
     { "path": "./packages/bash/bash" },
     { "path": "./packages/compact/compact" },
+    { "path": "./packages/compact/compact-basic" },
     { "path": "./packages/llm/llm-deepseek" },
     { "path": "./packages/llm/llm-pi-ai" },
     { "path": "./packages/bash/bash-local" },