refactor: replace Biome with oxlint + oxfmt

Migrate the entire monorepo from Biome 2.4.7 to oxlint 1.56.0 (linter)
and oxfmt 0.41.0 (formatter) for faster lint/format and broader rule
coverage.

- Add `.oxlintrc.json` with React, TypeScript, unicorn, import plugins
  and correctness/suspicious categories
- Add `.oxfmtrc.json` with 2-space indent, import sorting, and Tailwind
  class sorting (all 30+ custom className attributes migrated)
- Add `docs/.oxlintrc.json` and `docs/.oxfmtrc.json` with Next.js plugin
- Update all 12 workspace package.json scripts: `oxlint`, `oxfmt`,
  `oxfmt --check`
- Add `format:check` turbo task and CI step
- Update VS Code settings/extensions to use `oxc.oxc-vscode`
- Update CI path triggers from `biome.json` to new config files
- Remove all `biome-ignore` comments and fix shadowed variables
- Delete `biome.json` and `docs/biome.json`
- Reformat entire codebase with oxfmt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/core/test/thumbhash.test.ts

@@ -1,12 +1,5 @@
-import {
-  afterEach,
-  beforeEach,
-  describe,
-  expect,
-  mock,
-  spyOn,
-  test,
-} from "bun:test";
+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";
@@ -52,14 +45,8 @@ describe("thumbhash generation", () => {
   });
 
   test("clears a stale episode thumbhash when regeneration fails", async () => {
-    testDb
-      .insert(titles)
-      .values({ id: "tv-1", tmdbId: 100, type: "tv", title: "Show" })
-      .run();
-    testDb
-      .insert(seasons)
-      .values({ id: "season-1", titleId: "tv-1", seasonNumber: 1 })
-      .run();
+    testDb.insert(titles).values({ id: "tv-1", tmdbId: 100, type: "tv", title: "Show" }).run();
+    testDb.insert(seasons).values({ id: "season-1", titleId: "tv-1", seasonNumber: 1 }).run();
     testDb
       .insert(episodes)
       .values({
@@ -74,11 +61,7 @@ describe("thumbhash generation", () => {
     nextBuffer = null;
     const hash = await generateEpisodeThumbHash("ep-1", "/new-still.png");
 
-    const episode = testDb
-      .select()
-      .from(episodes)
-      .where(eq(episodes.id, "ep-1"))
-      .get();
+    const episode = testDb.select().from(episodes).where(eq(episodes.id, "ep-1")).get();
 
     expect(hash).toBeNull();
     expect(episode?.stillThumbHash).toBeNull();