feat: replace Directus with custom Node.js GraphQL backend

Removes Directus 11 and replaces it with a lean, purpose-built backend:
- packages/backend/: Fastify v5 + GraphQL Yoga v5 + Pothos (code-first)
  with Drizzle ORM, Redis sessions (session_token cookie), argon2 auth,
  Nodemailer, fluent-ffmpeg, and full gamification system ported from bundle
- Frontend: @directus/sdk replaced by graphql-request v7; services.ts fully
  rewritten with identical signatures; directus.ts now re-exports from api.ts
- Cookie renamed directus_session_token → session_token
- Dev proxy target updated 8055 → 4000
- compose.yml: Directus service removed, backend service added (port 4000)
- Dockerfile.backend: new multi-stage image with ffmpeg
- Dockerfile: bundle build step and ffmpeg removed from frontend image
- data-migration.ts: one-time script to migrate all Directus/sexy_ tables

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/backend/src/db/schema/recordings.ts

@@ -0,0 +1,73 @@
+import {
+  pgTable,
+  text,
+  timestamp,
+  boolean,
+  integer,
+  pgEnum,
+  index,
+  uniqueIndex,
+  jsonb,
+} from "drizzle-orm/pg-core";
+import { users } from "./users.js";
+import { videos } from "./videos.js";
+
+export const recordingStatusEnum = pgEnum("recording_status", [
+  "draft",
+  "published",
+  "archived",
+]);
+
+export const recordings = pgTable(
+  "recordings",
+  {
+    id: text("id").primaryKey().$defaultFn(() => crypto.randomUUID()),
+    title: text("title").notNull(),
+    description: text("description"),
+    slug: text("slug").notNull(),
+    duration: integer("duration").notNull(),
+    events: jsonb("events").$type<object[]>().default([]),
+    device_info: jsonb("device_info").$type<object[]>().default([]),
+    user_id: text("user_id")
+      .notNull()
+      .references(() => users.id, { onDelete: "cascade" }),
+    status: recordingStatusEnum("status").notNull().default("draft"),
+    tags: text("tags").array().default([]),
+    linked_video: text("linked_video").references(() => videos.id, {
+      onDelete: "set null",
+    }),
+    featured: boolean("featured").default(false),
+    public: boolean("public").default(false),
+    original_recording_id: text("original_recording_id"),
+    date_created: timestamp("date_created").notNull().defaultNow(),
+    date_updated: timestamp("date_updated"),
+  },
+  (t) => [
+    uniqueIndex("recordings_slug_idx").on(t.slug),
+    index("recordings_user_idx").on(t.user_id),
+    index("recordings_status_idx").on(t.status),
+    index("recordings_public_idx").on(t.public),
+  ],
+);
+
+export const recording_plays = pgTable(
+  "recording_plays",
+  {
+    id: text("id").primaryKey().$defaultFn(() => crypto.randomUUID()),
+    recording_id: text("recording_id")
+      .notNull()
+      .references(() => recordings.id, { onDelete: "cascade" }),
+    user_id: text("user_id").references(() => users.id, { onDelete: "set null" }),
+    duration_played: integer("duration_played").default(0),
+    completed: boolean("completed").default(false),
+    date_created: timestamp("date_created").notNull().defaultNow(),
+    date_updated: timestamp("date_updated"),
+  },
+  (t) => [
+    index("recording_plays_recording_idx").on(t.recording_id),
+    index("recording_plays_user_idx").on(t.user_id),
+  ],
+);
+
+export type Recording = typeof recordings.$inferSelect;
+export type NewRecording = typeof recordings.$inferInsert;