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/shared/model-resolution-pipeline.ts

@@ -116,8 +116,10 @@ export function resolveModelPipeline(
           if (parts.length >= 2) {
             const provider = parts[0]
             if (connectedSet.has(provider)) {
-              log("Model resolved via user fallback_models (connected provider)", { model })
-              return { model, provenance: "provider-fallback", attempted }
+              const modelName = parts.slice(1).join("/")
+              const transformedModel = `${provider}/${transformModelForProvider(provider, modelName)}`
+              log("Model resolved via user fallback_models (connected provider)", { model: transformedModel, original: model })
+              return { model: transformedModel, provenance: "provider-fallback", attempted }
             }
           }
         }