fix: replace orphaned invalidateStateCache() calls and remove dead test

- Replace 2 remaining invalidateStateCache() calls with invalidateAllCaches()
  in auto.ts phantom skip loop recovery paths (lines 2473, 2551)
- Remove commit-message.test.ts which referenced the removed
  deriveCommitMessage export from auto.ts

src/resources/extensions/gsd/auto.ts

@@ -2470,7 +2470,7 @@ async function dispatchNextUnit(
           // Milestone is complete — evicting this key would fight self-heal.
           // Clear skip counter and re-dispatch from fresh state.
           unitConsecutiveSkips.delete(idempotencyKey);
-          invalidateStateCache();
+          invalidateAllCaches();
           ctx.ui.notify(
             `Phantom skip loop cleared: ${unitType} ${unitId} belongs to completed milestone ${skippedMid}. Re-dispatching from fresh state.`,
             "info",
@@ -2548,7 +2548,7 @@ async function dispatchNextUnit(
         : false;
       if (skippedMilestoneComplete2) {
         unitConsecutiveSkips.delete(idempotencyKey);
-        invalidateStateCache();
+        invalidateAllCaches();
         ctx.ui.notify(
           `Phantom skip loop cleared: ${unitType} ${unitId} belongs to completed milestone ${skippedMid2}. Re-dispatching from fresh state.`,
           "info",