refactor: low-regret cleanup across core, engine, dashboard

- core: extract ai-engine-loader.ts to share @fusion/engine dynamic-import
  boilerplate between ai-summarize and memory-compaction (incl. AgentMessage
  type); collapse getInbox/getOutbox, listInsights/countInsights,
  listRuns/countRuns, and three hasProjectDb* variants behind shared helpers.
- core: drop unused pluginLoaderLog export; tighten two `any` casts
  (db.walCheckpoint row, plugin-loader error.code).
- engine: extract resolveRoleFallback helper from buildSessionSkillContext/Sync;
  remove 22 stale `eslint-disable no-explicit-any` directives across
  project-engine, self-healing, triage, worktree-pool.
- dashboard: apply ESLint autofix (let→const, empty `interface extends`→type).

All three packages: typecheck clean, full test suites pass (14,414 tests),
builds clean. Net lint: -31 warnings. No public behavior changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/engine/src/triage.ts

@@ -1364,7 +1364,7 @@ export class TriageProcessor {
           // Re-read task detail to get latest user comments for the reviewer
           const currentDetail = await store.getTask(taskId);
           const currentUserComments = (currentDetail.comments || []).filter(
-            // eslint-disable-next-line @typescript-eslint/no-explicit-any
+
             (c: any) => c.author === "user",
           );
 
@@ -1510,7 +1510,7 @@ export class TriageProcessor {
     }
 
     const parsedDeps = await this.store.parseDependenciesFromPrompt(task.id);
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+
     const taskUpdates: Record<string, any> = { status: null, error: null };
 
     if (parsedDeps.length > 0) {