chore(deps): update Node setup and Docker metadata/build Actions
Consolidates #259 (Docker metadata 6), #260 (setup-node 7), and the original #261 (Docker build/push 7), preserving their commits. Each original PR contains current main; the combined branch is up to date and has green repository CI.
Reviewed the major-release notes against the workflow inputs and environment settings. The Docker Actions use Node 24, already supported by the GitHub-hosted runner. The repository uses no removed Buildx inputs/outputs or deprecated build-summary environment variables. setup-node continues to configure Node 22 and pnpm caching.
A separate validation branch differs only by a temporary workflow and passed a real runner proof: setup-node 7 with the npm registry configuration used by SDK release installs, both frozen installs, SDK type checking/tests/build, Buildx 4, GHCR login 4, metadata 6, and build/push 7. It built and loaded a local image and verified its Node runtime, compiled server, and migration file. Registry package access was read-only and image push was disabled. Actions proof. The temporary workflow is excluded from this merge.
Application code and lockfiles are identical to the tree that passed full pnpm check, security audit, and pnpm verify:architecture at https://github.com/Hazzng/sql-fs/actions/runs/38496142358. The earlier Buildx/login merges also passed the release workflow on main.
Use a merge commit to preserve all three original PR heads.