refactor(repo): consolidate openflare-server to root and move subprojects to internal/apps

- Merge all files inside openflare-server to the repository root directory.
- Relocate agent, relay, and flared subprojects from internal/ to internal/apps/.
- Combine docker-compose files and update build context paths to root.
- Update GitHub workflows and Dockerfiles to refer to new directories and package names.
- Rewrite Go package imports across all files.
- Resolve database renew test race condition and clean up docs.

.github/workflows/github-pages.yml

@@ -17,7 +17,7 @@ jobs:
         env:
           CI: ""
         run: |
-          cd openflare-server/frontend
+          cd frontend
           corepack enable
           pnpm install --frozen-lockfile
           pnpm build:embed
@@ -27,4 +27,4 @@ jobs:
         with:
           ACCESS_TOKEN: ${{ secrets.ACCESS_TOKEN }}
           BRANCH: gh-pages # The branch the action should deploy to.
-          FOLDER: openflare-server/frontend/out # The folder the action should deploy.
+          FOLDER: frontend/out # The folder the action should deploy.