feat(plh): flag plugin-agent frontmatter Claude Code ignores (v5.5.0 / E)

Plugin subagents silently ignore `hooks`/`mcpServers`/`permissionMode`
frontmatter — these are honored only for user/project agents in
.claude/agents/ (code.claude.com/docs sub-agents). Setting them in a
plugin agent is dead config; `permissionMode` is MEDIUM because it
implies a restriction Claude Code does not apply (false security).
hooks/mcpServers are LOW.

Additive to PLH's agent-frontmatter loop (no new scanner, count stays
13). One humanizer pattern covers the three field titles. Hermetic
temp-fixture test (positive + negative). Suite 954 -> 957, byte-stable.

Part of v5.5.0 "steering-model I". Foundation (active-config-reader
enumeration) deferred to v5.6 with B — A/E are additive and don't
consume it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ter3E2JSi1Khgmuf2kady8

README.md

@@ -12,7 +12,7 @@
 ![Commands](https://img.shields.io/badge/commands-18-green)
 ![Agents](https://img.shields.io/badge/agents-6-orange)
 ![Hooks](https://img.shields.io/badge/hooks-4-red)
-![Tests](https://img.shields.io/badge/tests-954+-brightgreen)
+![Tests](https://img.shields.io/badge/tests-957+-brightgreen)
 ![License](https://img.shields.io/badge/license-MIT-lightgrey)
 
 A Claude Code plugin that checks configuration health, suggests context-aware improvements, and auto-fixes issues — `CLAUDE.md`, `settings.json`, hooks, rules, MCP servers, `@imports`, and plugins. 13 deterministic scanners across 10 quality areas, context-aware feature recommendations, auto-fix with backup/rollback, a prompt-cache-aware Token Hotspots scanner with optional API-calibrated `--accurate-tokens` mode, plus cache-prefix stability, dead-tool, and cross-plugin collision detection. Zero external dependencies.