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>

sdk/src/query/config-mutation.ts

@@ -63,7 +63,8 @@ const VALID_CONFIG_KEYS = new Set([
   'workflow.research_before_questions',
   'workflow.discuss_mode',
   'workflow.skip_discuss',
-  'workflow._auto_chain_active',
+  'workflow.ui_review',
+  'workflow.max_discuss_passes',
   'workflow.use_worktrees',
   'workflow.code_review',
   'workflow.code_review_depth',
@@ -72,6 +73,7 @@ const VALID_CONFIG_KEYS = new Set([
   'planning.commit_docs', 'planning.search_gitignored',
   'workflow.subagent_timeout',
   'hooks.context_warnings',
+  'hooks.workflow_guard',
   'features.thinking_partner',
   'features.global_learnings',
   'learnings.max_inject',