[djthorpe]

Two changes to config, and to the TypeScript package's ConfigController.

Rebuilt servers offer Refresh. The controller only offered Refresh when the version changed. A server rebuilt with the same version, such as while it's developed (git describe doesn't change until a commit), just said "The server is back".

• /config.json now has build: when the server was built, from pkg/version.BuildTime() (the BuildDate ldflag, which go-server's Makefile already sets).
• A server back with another build is upgraded. The notification and gs-server-status's tooltip then say it's been rebuilt, with Refresh.
• Servers whose Makefile doesn't set BuildDate behave as before. The README says how to set it.

A page reads /config.json once. A page reads its config to find the API, then made the controller read it again. ConfigController now takes config, the config the page has read, and starts up with it.

const page = await getConfig();
const changes = new ChangesController(configClient(page));
const config = new ConfigController(changes, { config: page, notifications });
changes.start();

[Copilot]

🟡 Changes recommended

The regression test can pass despite redundant configuration fetches, and the documented Makefile substitution can leave BuildDate empty.

2 open issues

• Assert connecting does not refetch configuration · New
• Use Makefile-compatible command substitution for BuildDate · New

What changed in this PR

This PR lets frontends detect same-version server rebuilds and offer a page refresh. It also lets ConfigController reuse configuration already loaded by the page, avoiding a duplicate initial request.

Changes:

• Expose the server’s build timestamp through /config.json.
• Detect rebuilds and show refresh notifications and status tooltips.
• Accept preloaded configuration, with updated tests and usage documentation.

File	Description
frontend/​test/​config-controller.test.ts	Add preloaded-configuration and rebuild tests.
frontend/​src/​config/​view.ts	Show rebuild-specific refresh tooltips.
frontend/​src/​config/​schema.ts	Add the optional build timestamp.
frontend/​src/​config/​controller.ts	Reuse preloaded configuration and detect changed builds.
frontend/​README.md	Document build timestamps and configuration reuse.
config/​config.go	Include the server build time in configuration responses.
config/​config_test.go	Cover the build field in handler responses.

_{Review effort: Balanced}