v0.7.3: UI cleanup — aligned Hosts pin form, native-chrome list filters, Link row reorder

Design-language cleanup of the v0.7.2 additions (no behaviour change).

Hosts:
- The Pin MAC form collapses to a single aligned 4-up row: MAC ·
  Label · Architecture · Boot binary. Target drops full-width onto its
  own line beneath them. The per-field hints that broke the row's
  alignment moved into the explanatory note below, so every control
  shares one baseline.

Storage:
- The image and unattended filter inputs are now wrapped in a
  label.field, so they inherit the standard text-field chrome (border,
  radius, height, focus ring) instead of the raw browser
  <input type=search> look. They span the full card width for
  continuity with the rest of the page.

Network:
- The 'Link' row moved below 'Public base URL'. Its joined
  operstate · speed · duplex · MAC string runs long, so placing it last
  lets it wrap at the bottom without shoving the other rows around.

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]>

Cargo.toml

@@ -12,7 +12,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.7.2"
+version = "0.7.3"
 edition = "2021"
 rust-version = "1.95"
 license = "MIT OR Apache-2.0"