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

scanners/lib/humanizer-data.mjs

@@ -706,6 +706,14 @@ export const TRANSLATIONS = {
       },
     },
     patterns: [
+      {
+        regex: /^Plugin agent sets ".+", which Claude Code ignores$/,
+        translation: {
+          title: 'A plugin agent sets a field Claude Code ignores',
+          description: 'Plugin subagents ignore the `hooks`, `mcpServers`, and `permissionMode` settings — only agents in `.claude/agents/` honor them. The field shown here has no effect, and `permissionMode` can give a false sense of restriction.',
+          recommendation: 'Remove the field, or move the agent into `.claude/agents/`, where it takes effect.',
+        },
+      },
       {
         regex: /^Missing required field in plugin\.json/,
         translation: {