feat: GBrain resolver — brain-first lookup and save-to-brain

New scripts/resolvers/gbrain.ts with two resolver functions:
- GBRAIN_CONTEXT_LOAD: search brain for context before skill starts
- GBRAIN_SAVE_RESULTS: save skill output to brain after completion

Placeholders added to 4 thinking skill templates (office-hours,
investigate, plan-ceo-review, retro). Resolves to empty string on
all hosts except gbrain via suppressedResolvers.

GBRAIN suppression added to all 9 non-gbrain host configs.

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

scripts/resolvers/index.ts

@@ -18,6 +18,7 @@ import { generateConfidenceCalibration } from './confidence';
 import { generateInvokeSkill } from './composition';
 import { generateReviewArmy } from './review-army';
 import { generateDxFramework } from './dx';
+import { generateGBrainContextLoad, generateGBrainSaveResults } from './gbrain';
 
 export const RESOLVERS: Record<string, ResolverFn> = {
   SLUG_EVAL: generateSlugEval,
@@ -62,4 +63,6 @@ export const RESOLVERS: Record<string, ResolverFn> = {
   REVIEW_ARMY: generateReviewArmy,
   CROSS_REVIEW_DEDUP: generateCrossReviewDedup,
   DX_FRAMEWORK: generateDxFramework,
+  GBRAIN_CONTEXT_LOAD: generateGBrainContextLoad,
+  GBRAIN_SAVE_RESULTS: generateGBrainSaveResults,
 };