- store: add tables and CRUD for sandboxes (with services), templates
(with services, clone-into-sandbox), environments (named key/value
sets), and routes (per-sandbox <service>_url overrides).
- api: split into one file per resource. handleSandboxes/handleSandboxByID
covers CRUD + 'clone from template' + 'deploy one service in a sandbox'
(which merges the sandbox's env into the request, picks the port,
and dispatches the deploy frame to the right node).
handleTemplates/handleTemplateByID, handleEnvironments/handleEnvironmentByID,
handlePushRoutes cover the rest. The control plane's repo->node
resolution still lives in resolveNode (api-gateway -> gateway,
everything else -> micro).
Achmad