refactor: enforce layered architecture by extracting all DB queries into @sofa/db/queries/*

- Create 18 new query modules under `packages/db/src/queries/` covering every domain (availability, cache, colors, credits, cron, discovery, image-cache, imports, integrations, lists, metadata, person, settings, system-health, thumbhash, title, tracking, webhooks)
- Remove all direct `db` client imports and raw Drizzle expressions from `@sofa/core` services and `apps/server` procedures/cron; replace with named query functions
- Extract cron DB helpers (`startCronRun`, `completeCronRun`, `failCronRun`, `getLibraryTitleIds`, `getStaleLibraryTitles`, etc.) into `packages/core/src/cron.ts`
- Extract integration DB helpers into `packages/core/src/integrations.ts`
- Add `drizzle-orm` as a direct dependency of `@sofa/db` and remove it from `@sofa/core`
- Update `AGENTS.md` to document the strict layered architecture rule

packages/core/test/import-processor.test.ts

@@ -1,6 +1,5 @@
 import { beforeEach, describe, expect, spyOn, test } from "bun:test";
 
-import { eq } from "@sofa/db/helpers";
 import {
   importJobs,
   titles,
@@ -11,6 +10,7 @@ import {
 } from "@sofa/db/schema";
 import {
   clearAllTables,
+  eq,
   insertMovieWatch,
   insertTvShow,
   insertUser,

packages/core/test/metadata-refresh.test.ts

@@ -1,8 +1,7 @@
 import { beforeEach, describe, expect, mock, test } from "bun:test";
 
-import { eq } from "@sofa/db/helpers";
 import { episodes, seasons, titles } from "@sofa/db/schema";
-import { clearAllTables, insertTitle, testDb } from "@sofa/db/test-utils";
+import { clearAllTables, eq, insertTitle, testDb } from "@sofa/db/test-utils";
 
 interface MockSeasonEpisode {
   episode_number: number;

packages/core/test/person-detail.test.ts

@@ -1,8 +1,7 @@
 import { afterEach, beforeEach, describe, expect, mock, spyOn, test } from "bun:test";
 
-import { eq } from "@sofa/db/helpers";
 import { personFilmography, persons } from "@sofa/db/schema";
-import { clearAllTables, testDb } from "@sofa/db/test-utils";
+import { clearAllTables, eq, testDb } from "@sofa/db/test-utils";
 
 const TINY_PNG = Buffer.from(
   "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVQIHWP4//8/AwAI/AL+X2NDNwAAAABJRU5ErkJggg==",

packages/core/test/thumbhash.test.ts

@@ -1,8 +1,7 @@
 import { afterEach, beforeEach, describe, expect, mock, spyOn, test } from "bun:test";
 
-import { eq } from "@sofa/db/helpers";
 import { episodes, seasons, titles } from "@sofa/db/schema";
-import { clearAllTables, testDb } from "@sofa/db/test-utils";
+import { clearAllTables, eq, testDb } from "@sofa/db/test-utils";
 
 const TINY_PNG = Buffer.from(
   "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVQIHWP4//8/AwAI/AL+X2NDNwAAAABJRU5ErkJggg==",

packages/core/test/tracking.test.ts

@@ -1,13 +1,20 @@
 import { beforeEach, describe, expect, test } from "bun:test";
 
-import { and, eq } from "@sofa/db/helpers";
 import {
   userEpisodeWatches,
   userMovieWatches,
   userRatings,
   userTitleStatus,
 } from "@sofa/db/schema";
-import { clearAllTables, insertTitle, insertTvShow, insertUser, testDb } from "@sofa/db/test-utils";
+import {
+  and,
+  clearAllTables,
+  eq,
+  insertTitle,
+  insertTvShow,
+  insertUser,
+  testDb,
+} from "@sofa/db/test-utils";
 
 import {
   getUserTitleInfo,