v0.81.0: retire drive-activation banner; add standalone "Kiszolgáló újraindítása" button

In the intermediary-mount model an enrolled drive binds live into the running
guest (no reboot), so the "… meghajtó aktiválásra vár / Újraindítás most" banner
was an obsolete relic — also dead since v0.78 (pendingActivationDrives keyed on
the raw MountPath vs the now-stable sp.Path). Removed the banner block +
activatePendingDrives JS (settings.html), the PendingDrives feed (handlers.go),
and the dead pendingActivationDrives helper + its unused internal/system import.

Renamed handleStorageActivate -> HandleServerReboot (split out a testable
serverReboot core), removed the /api/storage/activate case, and mounted the
handler at the new non-storage route /api/server/reboot (RequireAuth+CsrfProtect).
The agent GuestReboot primitive is reused unchanged.

Added the standalone "Kiszolgáló újraindítása" settings card (sibling to the
controller-only "Vezérlő újraindítása"), reusing the pollRestart() loop.

Test: TestHandleServerReboot_CallsGuestReboot (fake diskAgent asserts GuestReboot
invoked once + 202). diskAgent/mockAgent gained GuestReboot.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PsnU2ASocYrvzqE82YDYW

CHANGELOG.md

@@ -1,5 +1,29 @@
 ## Changelog
 
+### v0.81.0 — retire the drive-activation banner; add a standalone "Kiszolgáló újraindítása" button (2026-06-23)
+- **Removed the obsolete drive-activation banner.** In the intermediary-mount model an enrolled drive
+  binds **live** into the running guest (agent `disks.go` — no `pct set -mpN`, no slot, no reboot), so
+  the "… meghajtó aktiválásra vár / Újraindítás most (~30 mp)" banner was a relic of the old per-drive
+  reboot model. It was also effectively dead since v0.78 (`pendingActivationDrives` keyed `attached` by
+  the agent's RAW `MountPath` but compared it to the now-STABLE `sp.Path`). Removed: the
+  `{{if .PendingDrives}}` banner block + `window.activatePendingDrives` JS (`settings.html`), the
+  `data["PendingDrives"]` feed (`handlers.go`), and the dead `pendingActivationDrives` helper +
+  its now-unused `internal/system` import (`storage_handlers.go`).
+- **Repointed the reboot endpoint to a non-storage route.** Renamed `handleStorageActivate` →
+  `HandleServerReboot` and split out a testable `serverReboot` core (mirrors `runStorageInit`); removed
+  the `/api/storage/activate` case from `ServeStorageAPI`; mounted the handler at the new
+  `/api/server/reboot` (same `RequireAuth` + `CsrfProtect`) in `cmd/controller/main.go`. The agent
+  `GuestReboot` primitive is reused unchanged. (`/api/storage/activate` now returns 404.)
+  *Note:* the handler is exported (`HandleServerReboot`) because `cmd/controller/main.go` wires it
+  cross-package — same convention as every other web handler mounted there.
+- **Added the standalone "Kiszolgáló újraindítása" settings card.** A deliberate full-server (guest)
+  restart affordance, a sibling to the existing "Vezérlő újraindítása" controller-only restart.
+  New `settings-card` + `restartServer()` JS (reuses the existing `pollRestart()` loop) in
+  `settings.html`; posts to `/api/server/reboot`.
+- **Test:** `TestHandleServerReboot_CallsGuestReboot` (`storage_handlers_test.go`) — a fake `diskAgent`
+  asserts `GuestReboot` is invoked exactly once and the response is 202 `{ok:true, rebooting:true}`.
+  `diskAgent`/`mockAgent` gained `GuestReboot`. Green gate: `go build ./... && go vet ./... && go test ./...`.
+
 ### v0.80.0 — disk card: show + act on the stable path, not the raw host mount (2026-06-23)
 - Follow-up to v0.78/0.79. The storage disk card displayed the drive's **raw** host PVE mount
   (`/mnt/<name>`) — which doesn't exist inside the guest — instead of the **stable** in-guest path