Add gate intensity modes: full, lean, and solo review control

Adds a --review flag to all 13 gate-using skills and a global
production/review-mode.txt config (set during /start). Full runs all
director gates, lean skips per-skill gates but keeps phase gates, solo
skips all directors. Documents modes in director-gates.md, WORKFLOW-GUIDE.md,
and README.md.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/create-architecture/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: create-architecture
 description: "Guided, section-by-section authoring of the master architecture document for the game. Reads all GDDs, the systems index, existing ADRs, and the engine reference library to produce a complete architecture blueprint before any code is written. Engine-version-aware: flags knowledge gaps and validates decisions against the pinned engine version."
-argument-hint: "[focus-area: full | layers | data-flow | api-boundaries | adr-audit]"
+argument-hint: "[focus-area: full | layers | data-flow | api-boundaries | adr-audit] [--review full|lean|solo]"
 user-invocable: true
 allowed-tools: Read, Glob, Grep, Write, Bash
 context: fork
@@ -17,6 +17,9 @@ It sits between design and implementation, and must exist before sprint planning
 **Distinct from `/architecture-decision`**: ADRs record individual point decisions.
 This skill creates the whole-system blueprint that gives ADRs their context.
 
+Extract `--review [full|lean|solo]` if present and store as the review mode
+override for this run (see `.claude/docs/director-gates.md`).
+
 **Argument modes:**
 - **No argument / `full`**: Full guided walkthrough — all sections, start to finish
 - **`layers`**: Focus on the system layer diagram only