v0.7.2: UI polish — list search, unified Hosts form, NIC link details, About refresh, spacing

Storage:
- Filter inputs for the Available images table (matches filename,
  detected family, category, source) and the Unattended files list
  (name, kind). Pure client-side; shown when there's more than one
  entry. Forty-image libraries are now navigable.

Hosts — one form, one mental model:
- The separate Boot rules card is gone. The Pin form gains
  'Architecture (optional)' next to Label (plus the v0.7.1 boot-binary
  pin): a full MAC with no architecture saves a per-host pin exactly as
  before; a MAC prefix and/or architecture saves a first-match-wins
  group rule. Saved rules render as a compact read-only 'Group rules'
  card with remove buttons.
- The boot-decision webhook keeps working via /api/boot-rules but no
  longer has a UI knob (operator feedback: not needed in the UI).
- Per-machine auto-deploy fields are rejected on group rules with a
  clear message (they're per-host values).

Network:
- New 'Link' row under NIC name: operstate · speed · duplex · port MAC,
  read from sysfs at startup (detect_link_info). Empty-degrades on
  non-Linux dev builds and virtual NICs. Confirms WHICH physical port
  answers PXE in multi-NIC/trunked environments.

About:
- Hero copy rewritten: positioning lead, three-pillar feature grid
  (Boot anything / Adapt to every machine / Run it in production), and
  the privacy + no-test-cert principles restated crisply.

Spacing:
- label.field:has(+ button) collapse fixes the doubled 30px gap above
  Queue 'Launch for all waiting' and Network 'Save' (now the same 16px
  as every other card action).

Validation: clippy clean, fmt clean, 299 workspace tests green, webui
syntax-checked. No protocol or boot-path changes in this release.

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

crates/http-api/tests/full_flow.rs

@@ -135,6 +135,7 @@ async fn build_state() -> (AppState, tempfile::TempDir) {
         started_at: time::OffsetDateTime::now_utc(),
         public_base_url: "http://127.0.0.1".into(),
         nic_name: "lo".into(),
+        nic_link: String::new(),
         subnet_mask: "255.0.0.0".into(),
         gateway: "127.0.0.1".into(),
     };