docs: update project documentation for v0.13.0.0

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -206,6 +206,8 @@ Templates contain the workflows, tips, and examples that require human judgment.
 | `{{REVIEW_DASHBOARD}}` | `gen-skill-docs.ts` | Review Readiness Dashboard for /ship pre-flight |
 | `{{TEST_BOOTSTRAP}}` | `gen-skill-docs.ts` | Test framework detection, bootstrap, CI/CD setup for /qa, /ship, /design-review |
 | `{{CODEX_PLAN_REVIEW}}` | `gen-skill-docs.ts` | Optional cross-model plan review (Codex or Claude subagent fallback) for /plan-ceo-review and /plan-eng-review |
+| `{{DESIGN_SETUP}}` | `resolvers/design.ts` | Discovery pattern for `$D` design binary, mirrors `{{BROWSE_SETUP}}` |
+| `{{DESIGN_SHOTGUN_LOOP}}` | `resolvers/design.ts` | Shared comparison board feedback loop for /design-shotgun, /plan-design-review, /design-consultation |
 
 This is structurally sound — if a command exists in code, it appears in docs. If it doesn't exist, it can't appear.
 
@@ -357,4 +359,4 @@ Tier 1 runs on every `bun test`. Tiers 2+3 are gated behind `EVALS=1`. The idea:
 - **No MCP protocol.** MCP adds JSON schema overhead per request and requires a persistent connection. Plain HTTP + plain text output is lighter on tokens and easier to debug.
 - **No multi-user support.** One server per workspace, one user. The token auth is defense-in-depth, not multi-tenancy.
 - **No Windows/Linux cookie decryption.** macOS Keychain is the only supported credential store. Linux (GNOME Keyring/kwallet) and Windows (DPAPI) are architecturally possible but not implemented.
-- **No iframe support.** Playwright can handle iframes but the ref system doesn't cross frame boundaries yet. This is the most-requested missing feature.
+- **No iframe auto-discovery.** `$B frame` supports cross-frame interaction (CSS selector, @ref, `--name`, `--url` matching), but the ref system does not auto-crawl iframes during `snapshot`. You must explicitly enter a frame context first.