feat(deploy): switch to Oracle MySQL, separate CI runner, docker-compose deploy

- Prisma schema: sqlite → mysql provider
- Migration SQL rewritten as MySQL DDL (utf8mb4, DATETIME(3), AUTO_INCREMENT)
- Add migration_lock.toml for mysql provider
- Dockerfile.backend: drop node:22/sqlite deps, use node:20-slim
- entrypoint.sh: replace SQLite first-run logic with prisma migrate deploy + db seed
- docker-compose.prod.yml: production compose for /opt/webapps/okr on web VPS
  - reads DB creds from /opt/webapps/webapp-mysql.env
  - reads app secrets from /opt/webapps/okr/.env.app (written by CI)
  - port 80 (frontend), no conflict with Gitea 3000/Vault 8200
- ci.yml deploy-okr: moves from ubuntu-latest (web VPS) to ci-runner (161.33.149.243)
  - builds images on CI runner VPS (no heavy build on web/Gitea VPS)
  - transfers images via docker save | gzip | ssh | docker load
  - deploys via SSH + docker compose up on web VPS
- scripts/setup-ci-runner.sh: one-time setup script for CI runner VPS

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

AINative_OKR_CASAN5/Dockerfile.backend

@@ -1,5 +1,5 @@
 # ─── Stage 1: Build ──────────────────────────────────────────────────────────
-FROM node:22-slim AS builder
+FROM node:20-slim AS builder
 
 WORKDIR /app
 
@@ -15,13 +15,10 @@ RUN npm ci
 COPY backend/src ./backend/src
 COPY backend/tsconfig*.json ./backend/
 
-# Generate Prisma client + compile TypeScript
 RUN cd backend && npx prisma generate && npx tsc -p tsconfig.build.json
 
 # ─── Stage 2: Runtime ────────────────────────────────────────────────────────
-FROM node:22-slim AS runtime
-
-# node:sqlite (setup-sqlite.mjs) requires Node 22 — this image satisfies that.
+FROM node:20-slim AS runtime
 
 WORKDIR /app
 
@@ -32,24 +29,19 @@ COPY backend/package.json ./backend/
 COPY frontend/package.json ./frontend/
 COPY backend/prisma ./backend/prisma
 
-# All deps (including devDeps) so that tsx (seed) and prisma CLI are available.
 RUN npm ci --ignore-scripts
 
-# Generate Prisma client in runtime image (CWD resolves schema at backend/prisma/schema.prisma)
 RUN cd backend && npx prisma generate
 
 COPY --from=builder /app/backend/dist ./backend/dist
-COPY backend/scripts ./backend/scripts
 COPY backend/entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
 WORKDIR /app/backend
 
-VOLUME ["/data"]
 EXPOSE 3001
 
 ENV PORT=3001
-ENV DATABASE_URL=file:/data/okr.db
 ENV NODE_ENV=production
 
 ENTRYPOINT ["/entrypoint.sh"]