feat(agents): W2/S1 plugin split — probe (sonnet) + advisor reasoner (opus) + plugin-gate include (BDR-077)

plugin-advisor keeps its name, becomes the opus REASONER: PHASE 1 bash
extracted to new plugin-probe (sonnet, facts-only PROBE REPORT), PHASE 4
apply + checkpoint hoisted to new lib/plugin-gate.md (main-loop include,
doc-commit.md x6 pattern). Fail-closed: advisor ERRORs on missing report.
4 consumers rewired (plugin-check, onboard, init-project, ship-feature).
In-wave planted-input smoke PASSED: probe report complete w/ fallbacks;
advisor consumed every planted field (monorepo per-package note, fast-libs
ctx7 reco) with zero re-detection; ERROR verdict on absent report.
Census §13 (81 pass). Note: new subagent_type registers next session —
resolution re-check before wave merge.

skills/plugin-check/SKILL.md

@@ -2,13 +2,19 @@
 name: plugin-check
 description: 'Audit active plugins vs project needs. Read-only advisory recommending enable/disable. Triggers: "plugin-check", "quels plugins".'
 argument-hint: '[ex: "React + FastAPI" or "Rust CLI, no frontend"]'
-allowed-tools: Read, Bash, Glob, Grep
+allowed-tools: Read, Bash, Glob, Grep, Agent
 ---
 
-Load and follow strictly: `$HOME/.claude/agents/plugin-advisor.md`.
+Run `$HOME/.claude/lib/plugin-gate.md` on the context below — dispatch
+plugin-probe (sonnet) → validation checkpoint → dispatch plugin-advisor
+(opus) → present the PLUGIN CHECK block (BDR-077: detection and reasoning
+dispatched, gates in this loop).
 
-Analyze active plugins + context below, produce PLUGIN ADVISOR REPORT.
+/plugin-check is READ-ONLY advisory: SKIP the gate's step 5 (apply) — show
+the advisor's exact toggle commands for the user instead. Never write; user
+toggles via `claude plugin enable/disable`.
 
-If `$HOME/.claude/agents/plugin-advisor.md` unreachable: emit `Plugin advisor agent missing.` and STOP. Never write — user toggles via `claude plugin enable/disable`.
+If `$HOME/.claude/lib/plugin-gate.md` unreachable: emit `Plugin gate include
+missing.` and STOP.
 
 $ARGUMENTS