v0.5.2: FleetDM login split, 3-slot branding, unattended installs

Authentication / login:
- Separate the local username/password form from the SSO "Sign in with …"
  button (FleetDM-style divider + optional IdP logo); credential fields no
  longer double as the SSO trigger. Settings → SSO copy now says SAML is live.

Branding — three slots (light / dark / client) on one row:
- Light/Dark feed the top-left mark + sign-in page by active theme (with
  cross-theme fallback; theme toggle swaps the logo live). Client feeds the
  PXE boot-menu background. Favicon pinned to the bundled mark via a new
  /assets/favicon.svg endpoint. Legacy single logo migrates to dark + client.
- BrandingStore refactored to per-slot storage; /api/branding/logo/:slot.

Unattended installs (Storage → Advanced):
- New UnattendedStore (iso-store) + /api/unattended upload/list/delete and a
  public templated serve at /unattended/:id (+ NoCloud seed dir for
  autoinstall). Accepts .ks/.cfg/.seed/.yaml/.yml/.xml/user-data; classified
  on upload; stored in its own unattended/ dir, never the ISO listing/menu.
- {{HOSTNAME}}/{{IP}}/{{MAC}} substituted per host at serve time.

Host pins + Queue profiles:
- HostBinding + QueueEntry carry an optional DeployProfile (auto_hostname /
  auto_ip / unattended_file). Hosts pin form + a per-device Queue "Profile"
  button collect them. On boot, a matched MAC has the right kernel arg
  injected (inst.ks= / preseed url= / autoinstall ds=nocloud-net) and the
  hostname/IP templated into the served answer file. DHCP stays proxy-only.

Storage:
- Remote shares default protocol is now NFS; updated descriptive copy.

235 tests green, clippy clean. Still a single static musl binary, pure Rust.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

crates/webui/src/index.html

@@ -13,7 +13,10 @@
        on the asset handlers, the practical caching window is one
        version. -->
   <link rel="stylesheet" href="/assets/app.css?v={{ASSET_VERSION}}" />
-  <link rel="icon" type="image/svg+xml" href="/assets/logo.svg?v={{ASSET_VERSION}}&r={{LOGO_REV}}" />
+  <!-- v0.5.2: favicon is pinned to the bundled OpenPXE mark (its own
+       endpoint, decoupled from operator branding) for tab-icon
+       continuity regardless of any uploaded light/dark/client logo. -->
+  <link rel="icon" type="image/svg+xml" href="/assets/favicon.svg?v={{ASSET_VERSION}}" />
   <!-- Theme is read from localStorage *before* paint to avoid the
        dark→light flash on every navigation. Falls back to the OS
        preference and finally to dark. -->