dashboard: the build pages are tabs of the dashboard

The build lifecycle used to be its own page with three sub-tabs. They are
now dashboard tabs (rebuild, meta, buildlogs) beside SW4RM and
P3RM1SS10NS: builds.js is a module tabs.js imports, so the dashboard's one
tab strip, /api/state snapshot and event stream (plus the meta_inputs_changed
and meta_update_running kinds) serve them, and the page, its bundle entry,
stylesheet and home tile are gone. The SW4RM banner's "view queue" link
points at the #rebuild tab, and the rebuild tab carries a count pill of the
rebuilds in flight.

An empty tab-count pill drew a "0": its display beat the UA [hidden] rule.

frontend/packages/dashboard/build.mjs

@@ -1,5 +1,5 @@
 // esbuild build for @hive/dashboard: one JS+CSS bundle per page (H0M3 at
-// `/`, dashboard/flow/core/builds at their own
+// `/`, dashboard/flow/core/stats at their own
 // `.html`), each named after its own entry point below — see the
 // `entryPoints`/`for` lists for the exact map, not repeated here to
 // avoid this comment drifting out of sync with the real build steps.
@@ -38,7 +38,6 @@ await build({
     src("home.js"),
     src("stats.js"),
     src("core.js"),
-    src("builds.js"),
   ],
   outdir: staticDir(""),
   bundle: true,
@@ -57,7 +56,7 @@ await build({
   // runs as its own esbuild invocation over different entry points.
   loader: { ".css": "text" },
   // `@hive/shared/jobq-graph.js` resolves to a real `.jsx` file
-  // (`JobqGraph.jsx`), pulled in transitively by `builds.js` — esbuild
+  // (`JobqGraph.jsx`), pulled in transitively by `tabs.js` via `builds.js` — esbuild
   // already picks the `jsx` loader for `.jsx` by extension, this just
   // sets the transform mode to match swarm-ui's (which also authors
   // this file). No other entry here uses JSX today; this doesn't turn
@@ -103,7 +102,6 @@ for (const entry of [
   "home.css",
   "stats.css",
   "core.css",
-  "builds.css",
 ]) {
   await build({
     entryPoints: [src(entry)],
@@ -120,7 +118,6 @@ for (const html of [
   "flow.html",
   "stats.html",
   "core.html",
-  "builds.html",
 ]) {
   copyFileSync(src(html), dist(html));
 }