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>

hosts/openclaw.ts

@@ -53,6 +53,8 @@ const openclaw: HostConfig = {
     'CODEX_SECOND_OPINION',
     'CODEX_PLAN_REVIEW',
     'REVIEW_ARMY',
+    'GBRAIN_CONTEXT_LOAD',
+    'GBRAIN_SAVE_RESULTS',
   ],
 
   runtimeRoot: {
@@ -69,8 +71,6 @@ const openclaw: HostConfig = {
 
   coAuthorTrailer: 'Co-Authored-By: OpenClaw Agent <agent@openclaw.ai>',
   learningsMode: 'basic',
-
-  adapter: './scripts/host-adapters/openclaw-adapter',
 };
 
 export default openclaw;