fix: close 3 Oracle-identified gaps in cache-bust fixes

- Wire clearInjectionCache into session lifecycle via
  onSessionCacheInvalidated (compaction + deletion now clear stale cache)
- Gate catch-path nudgePlacements.clear behind isCacheBustingPass
  (defer-pass exceptions no longer trigger re-anchoring)

Author: ualtinok

src/hooks/magic-context/hook.ts

@@ -25,6 +25,7 @@ import { getErrorMessage } from "../../shared/error-message";
 import { log } from "../../shared/logger";
 import { createMagicContextCommandHandler } from "./command-handler";
 import { createEventHandler } from "./event-handler";
+import { clearInjectionCache } from "./inject-compartments";
 import { createNudger } from "./nudger";
 import { createTextCompleteHandler } from "./text-complete";
 import { createNudgePlacementStore, createTransform } from "./transform";
@@ -188,7 +189,10 @@ export function createMagicContextHook(deps: MagicContextDeps) {
         tagger: deps.tagger,
         db,
         nudgePlacements,
-        onSessionCacheInvalidated: deps.onSessionCacheInvalidated,
+        onSessionCacheInvalidated: (sessionId: string) => {
+            clearInjectionCache(sessionId);
+            deps.onSessionCacheInvalidated?.(sessionId);
+        },
     });
 
     const runDreamQueueInBackground = (): void => {

src/hooks/magic-context/transform-postprocess-phase.ts

@@ -229,7 +229,8 @@ export function runPostTransformPhase(args: RunPostTransformPhaseArgs): void {
     } catch (error) {
         sessionLog(args.sessionId, "transform failed applying pending operations:", error);
         updateSessionMeta(args.db, args.sessionId, { lastTransformError: getErrorMessage(error) });
-        args.nudgePlacements.clear(args.sessionId);
+        // Only clear on cache-busting passes to avoid re-anchor on next defer.
+        if (isCacheBustingPass) args.nudgePlacements.clear(args.sessionId);
     }
     // Only clear nudge placements on cache-busting passes. Clearing on defer would
     // cause the next pass to re-anchor the nudge on a cached assistant message (Finding 2).