docs(dox): build out the DOX AGENTS.md hierarchy

Root Child DOX Index assembled, plus a per-module AGENTS.md across the tree
(core/*, infrastructure/*, apps/*, testing/*, and docs/examples/frontend/etc),
each following the DOX section shape: Purpose, Ownership, Local Contracts,
Work Guidance, Verification, Child DOX Index.

apps/cli/AGENTS.md

@@ -0,0 +1,30 @@
+# apps/cli
+
+## Purpose
+
+Clikt-based command-line interface. Translates user commands into HTTP requests and WebSocket connections against `apps/server`.
+
+## Ownership
+
+All sources under `apps/cli/src/`.
+
+## Local Contracts
+
+- Commands: `session`, `run`, `task`, `provider`, `approve`, `undo`, `events`, `status`, `replay`, `stats`, `health`
+- Communicates with server via HTTP REST and WebSocket (`CliWsClient`)
+- No business logic; all orchestration is delegated to the server
+
+## Work Guidance
+
+- Follow Kotlin rules in root CLAUDE.md (runCatching, suspend, no blocking I/O on main thread)
+- New commands go under `commands/`, follow the existing Clikt subcommand pattern
+
+## Verification
+
+```
+./gradlew :apps:cli:test --rerun-tasks
+```
+
+## Child DOX Index
+
+No child AGENTS.md (leaf module).