fix: correct VALID_CONFIG_KEYS — remove internal state key, add missing public keys, migration hints (#2561)

* fix(#2530-2535): correct VALID_CONFIG_KEYS set — remove internal state key, add missing public keys, add migration hints

- Remove workflow._auto_chain_active from VALID_CONFIG_KEYS (internal runtime state, not user-settable) (#2530)
- Add hooks.workflow_guard to VALID_CONFIG_KEYS (read by gsd-workflow-guard.js hook, already documented) (#2531)
- Add workflow.ui_review to VALID_CONFIG_KEYS (read in autonomous.md via config-get) (#2532)
- Add workflow.max_discuss_passes to VALID_CONFIG_KEYS (read in discuss-phase.md via config-get) (#2533)
- Add CONFIG_KEY_SUGGESTIONS entries for sub_repos → planning.sub_repos and plan_checker → workflow.plan_check (#2535)
- Document workflow.ui_review and workflow.max_discuss_passes in docs/CONFIGURATION.md
- Clear INTERNAL_KEYS exemption in parity test (workflow._auto_chain_active removed from schema entirely)
- Add regression test file tests/bug-2530-valid-config-keys.test.cjs covering all 6 bugs

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

* fix: align SDK VALID_CONFIG_KEYS with CJS — remove internal key, add missing public keys

- Remove workflow._auto_chain_active from SDK (internal runtime state, not user-settable)
- Add workflow.ui_review, workflow.max_discuss_passes, hooks.workflow_guard to SDK
- Add ui_review and max_discuss_passes to Full Schema example in CONFIGURATION.md

Resolves CodeRabbit review on #2561.

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/CONFIGURATION.md

@@ -30,10 +30,12 @@ GSD stores project settings in `.planning/config.json`. Created during `/gsd-new
     "nyquist_validation": true,
     "ui_phase": true,
     "ui_safety_gate": true,
+    "ui_review": true,
     "node_repair": true,
     "node_repair_budget": 2,
     "research_before_questions": false,
     "discuss_mode": "discuss",
+    "max_discuss_passes": 3,
     "skip_discuss": false,
     "tdd_mode": false,
     "text_mode": false,
@@ -139,10 +141,12 @@ All workflow toggles follow the **absent = enabled** pattern. If a key is missin
 | `workflow.nyquist_validation` | boolean | `true` | Test coverage mapping during plan-phase research |
 | `workflow.ui_phase` | boolean | `true` | Generate UI design contracts for frontend phases |
 | `workflow.ui_safety_gate` | boolean | `true` | Prompt to run /gsd-ui-phase for frontend phases during plan-phase |
+| `workflow.ui_review` | boolean | `true` | Run visual quality audit (`/gsd-ui-review`) after phase execution in autonomous mode. When `false`, the UI audit step is skipped. |
 | `workflow.node_repair` | boolean | `true` | Autonomous task repair on verification failure |
 | `workflow.node_repair_budget` | number | `2` | Max repair attempts per failed task |
 | `workflow.research_before_questions` | boolean | `false` | Run research before discussion questions instead of after |
 | `workflow.discuss_mode` | string | `'discuss'` | Controls how `/gsd-discuss-phase` gathers context. `'discuss'` (default) asks questions one-by-one. `'assumptions'` reads the codebase first, generates structured assumptions with confidence levels, and only asks you to correct what's wrong. Added in v1.28 |
+| `workflow.max_discuss_passes` | number | `3` | Maximum number of question rounds in discuss-phase before the workflow stops asking. Useful in headless/auto mode to prevent infinite discussion loops. |
 | `workflow.skip_discuss` | boolean | `false` | When `true`, `/gsd-autonomous` bypasses the discuss-phase entirely, writing minimal CONTEXT.md from the ROADMAP phase goal. Useful for projects where developer preferences are fully captured in PROJECT.md/REQUIREMENTS.md. Added in v1.28 |
 | `workflow.text_mode` | boolean | `false` | Replaces AskUserQuestion TUI menus with plain-text numbered lists. Required for Claude Code remote sessions (`/rc` mode) where TUI menus don't render. Can also be set per-session with `--text` flag on discuss-phase. Added in v1.28 |
 | `workflow.use_worktrees` | boolean | `true` | When `false`, disables git worktree isolation for parallel execution. Users who prefer sequential execution or whose environment does not support worktrees can disable this. Added in v1.31 |