chore: convert to Turborepo + npm workspaces monorepo

- Move React/Vite frontend to apps/web/ (@budgetwise/web)
- Add apps/appwrite/ (@budgetwise/appwrite) to source-control the
  Appwrite backend: declarative schema in appwrite.json (5 collections),
  CLI-based deploy.sh for containerized use, functions/ dir for future
  Appwrite Functions
- Add turbo.json for task orchestration (build, deploy, dev)
- Replace .gitlab-ci.yml with Woodpecker CI pipelines in .woodpecker/:
    web-production.yml  — push to main → build + rsync to prod
    web-staging.yml     — push to staging → build + rsync to staging
    web-preview.yml     — PR open → deploy to {pr}.{domain}; PR close → cleanup
    appwrite.yml        — schema changes in apps/appwrite/ → CLI deploy
- All secrets injected via Woodpecker CI (no committed .env files)

.woodpecker/web-preview.yml

@@ -0,0 +1,78 @@
+# ── Web: Preview (Pull Requests) ──────────────────────────────────────────────
+# Triggered on pull_request open/sync → deploys to https://{pr-number}.{base_domain}
+# Triggered on pull_request_closed       → cleans up the preview directory
+#
+# Preview environments share staging Appwrite credentials.
+# PR number is available as $CI_COMMIT_PULL_REQUEST.
+#
+# Required Woodpecker secrets:
+#   base_domain                e.g. budget.kushalgaywala.com
+#   staging_appwrite_endpoint
+#   staging_appwrite_project_id
+#   ssh_private_key
+#   deploy_host
+#   deploy_user
+#   deploy_path
+# ─────────────────────────────────────────────────────────────────────────────
+
+when:
+  - event: [pull_request, pull_request_closed]
+
+steps:
+  - name: build
+    image: node:20-alpine
+    environment:
+      BASE_DOMAIN:
+        from_secret: base_domain
+      VITE_APPWRITE_ENDPOINT:
+        from_secret: staging_appwrite_endpoint
+      VITE_APPWRITE_PROJECT_ID:
+        from_secret: staging_appwrite_project_id
+    commands:
+      - export MR_URL="https://$CI_COMMIT_PULL_REQUEST.$BASE_DOMAIN"
+      - npm ci
+      - VITE_APP_URL=$MR_URL npm run build:preview -w @budgetwise/web
+    when:
+      - event: pull_request
+
+  - name: deploy
+    image: alpine
+    environment:
+      SSH_PRIVATE_KEY:
+        from_secret: ssh_private_key
+      DEPLOY_HOST:
+        from_secret: deploy_host
+      DEPLOY_USER:
+        from_secret: deploy_user
+      DEPLOY_PATH:
+        from_secret: deploy_path
+    commands:
+      - apk add --no-cache rsync openssh-client
+      - eval $(ssh-agent -s)
+      - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add -
+      - mkdir -p ~/.ssh && chmod 700 ~/.ssh
+      - ssh-keyscan -H "$DEPLOY_HOST" >> ~/.ssh/known_hosts
+      - rsync -avz --delete apps/web/dist/ "$DEPLOY_USER@$DEPLOY_HOST:$DEPLOY_PATH/mr-$CI_COMMIT_PULL_REQUEST/"
+    when:
+      - event: pull_request
+
+  - name: cleanup
+    image: alpine
+    environment:
+      SSH_PRIVATE_KEY:
+        from_secret: ssh_private_key
+      DEPLOY_HOST:
+        from_secret: deploy_host
+      DEPLOY_USER:
+        from_secret: deploy_user
+      DEPLOY_PATH:
+        from_secret: deploy_path
+    commands:
+      - apk add --no-cache openssh-client
+      - eval $(ssh-agent -s)
+      - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add -
+      - mkdir -p ~/.ssh && chmod 700 ~/.ssh
+      - ssh-keyscan -H "$DEPLOY_HOST" >> ~/.ssh/known_hosts
+      - ssh "$DEPLOY_USER@$DEPLOY_HOST" "rm -rf $DEPLOY_PATH/mr-$CI_COMMIT_PULL_REQUEST"
+    when:
+      - event: pull_request_closed