chore(agent): drop .claude/skills — AGENTS.md carries the routing

The skill shims became redundant once the auto-loaded entry point
(CLAUDE.md → AGENTS.md) explicitly instructs reading VERIFICATION.md /
THEME-DESIGN.md; their only remaining value was explicit /nomarchy and
/theme invocation. The adapter is now permissions + subagent defs only.
References updated (AGENTS.md, agent/README.md, docs/README.md, README
tree, MEMORY.md hygiene note).

Verification: V0 (docs/meta only).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/README.md

@@ -21,7 +21,7 @@ tree for the same facts.
 |------|------|
 | [../AGENTS.md](../AGENTS.md) | Agent entry point, any vendor/harness (`CLAUDE.md` symlinks to it) |
 | [../agent/README.md](../agent/README.md) | Agent instructions + **executable** loop state: BACKLOG, LOOP, VERIFICATION, … |
-| [../.claude/](../.claude/) | Claude Code adapter only: permissions + subagent/skill shims |
+| [../.claude/](../.claude/) | Claude Code adapter only: permissions + subagent defs |
 
 ## How work flows