fix: resolve publish blockers for v3.7.4→v3.8.0 release

- Fix #1991 crash: optional chaining for task-history sessionID access
- Fix #1992 think-mode: add antigravity entries to HIGH_VARIANT_MAP
- Fix #1949 Copilot premium misattribution: use createInternalAgentTextPart
- Fix #1982 load_skills: pass directory to discoverSkills for project-level skills
- Fix command priority: sort scopePriority before .find(), project-first return
- Fix Google provider transform: apply in userFallbackModels path
- Fix ralph-loop TUI: optional chaining for event handler
- Fix runtime-fallback: unify dual fallback engines, remove HTTP 400 from retry,
  fix pendingFallbackModel stuck state, add priority gate to skip model-fallback
  when runtime-fallback is active
- Fix Prometheus task system: exempt from todowrite/todoread deny
- Fix background_output: default full_session to true
- Remove orphan hooks: hashline-edit-diff-enhancer (redundant with hashline_edit
  built-in diff), task-reminder (dead code)
- Remove orphan config entries: 3 stale hook names from Zod schema
- Fix disabled_hooks schema: accept arbitrary strings for forward compatibility
- Register json-error-recovery hook in tool-guard pipeline
- Add disabled_hooks gating for question-label-truncator, task-resume-info,
  claude-code-hooks
- Update test expectations to match new behavior

src/plugin-config.test.ts

@@ -180,7 +180,7 @@ describe("parseConfigPartially", () => {
 
       expect(result).not.toBeNull();
       expect(result!.agents?.oracle?.model).toBe("openai/gpt-5.2");
-      expect(result!.disabled_hooks).toBeUndefined();
+      expect(result!.disabled_hooks).toEqual(["not-a-real-hook"]);
     });
   });
 
@@ -199,7 +199,7 @@ describe("parseConfigPartially", () => {
 
       expect(result).not.toBeNull();
       expect(result!.agents).toBeUndefined();
-      expect(result!.disabled_hooks).toBeUndefined();
+      expect(result!.disabled_hooks).toEqual(["not-a-real-hook"]);
     });
   });