v0.2.0 — pre-beta: per-MAC bindings, /metrics, themes, animated forge

This is the bulk pre-beta cleanup pass. Bumps the workspace to 0.2.0.
Test count is 56 -> 66 (+10), clippy is fully clean across the
workspace (was several dozen warnings).

## New features

**Per-MAC host bindings** (Tinkerbell smee pattern). New
`HostBindings` registry maps a MAC -> preferred boot target, persisted
to <work_dir>/hosts.json. The DHCP reply now embeds `?mac=${mac}` in
the boot.ipxe URL; iPXE substitutes the literal MAC client-side, so
the HTTP layer can short-circuit straight to the bound target instead
of rendering the menu. Reserved menu shortcuts (`_local`, `_gate`,
`_tools_menu`) are valid targets too. New /api/hosts CRUD + a Hosts
tab in the sidebar.

**Prometheus `/metrics`** endpoint. Tiny lock-free implementation —
just AtomicU64s and a Display impl, no `prometheus` / `metrics-rs`
dep. Counters: DHCP replies (per arch label), DHCP declined, TFTP
transfers (per status), TFTP bytes, HTTP requests (per route).
Gauges: ISO count, client count, gate count, gate-imaging, NFS active
mounts, uptime, build info. Plain text exposition format,
text/plain;version=0.0.4 content-type, no auth (all metric values are
non-sensitive counts).

**Light + dark themes**. CSS tokens on `:root` and
`:root[data-theme=light]`, swap by toggle button (top-right) or `T`
hotkey. Persisted in localStorage; pre-paint inline script avoids
dark<->light flash. Light palette designed against the Netbox Labs
reference screenshot — near-white surfaces, soft grey dividers,
accent unchanged for brand consistency. Terminal pane stays dark in
both themes (it's a console, that's the right read).

**Animated SVG logo + forge widget**. New `logo.svg` is a refined
silver/grey anvil. New `anvil-forge.svg` adds rising sparks and a
pulsing underglow via SMIL — pure SVG, no GIF, no JS animation loop.
Used:
  - in the **forge progress** widget on Dashboard + Forge Gate, paired
    with a `linear-gradient(warn -> accent)` bar with a moving sheen;
    goes idle (greyscale, no sheen) at zero imaging load
  - in the page-load `<div class=loader>` that replaces the old
    "Loading..." text

## Code cleanup pass

`cargo clippy --workspace --all-targets` is now warning-free. Spot
fixes across the tree:
  - `format!()`-into-`String` -> `std::fmt::Write::write!`
  - manual reverse comparators -> `Reverse`
  - `map_or(false, ...)` -> `is_some_and`
  - redundant closures -> method references
  - `r#"..."#` raw strings without `"` -> `r"..."`
  - `std::io::Error::new(Other, ...)` -> `Error::other`
  - `as i32` on `c.id()` -> `cast_signed()`
  - merged identical match arms

## Windows workflow validation

New integration test synthesizes an ISO9660 with the SOURCES\\BOOT.WIM
sentinel, uploads it, asserts:
  1. introspection labels it `windows_pe` with has_boot_wim=true,
  2. the boot entry is `BootKind::Wimboot` with all five canonical
     files (bootmgr, bootmgr.efi, bcd, boot.sdi, boot.wim),
  3. the rendered iPXE script chains wimboot with `initrd --name`
     entries for each file, and
  4. NO trust-store strings appear in the rendered output: bcdedit,
     testsigning, certutil, httpdisk, and test-signed are all
     explicitly forbidden as a hard guarantee.

WinPE bootstrap (startnet.cmd) picks up the Bootimus v0.1.58 lessons:
explicit `net start Workstation` before `net use` to avoid the SMB
client lazy-init race, and surfaces errors instead of blind retries.

## Docs

architecture.md gains a "Phase 5" section explaining the host-bindings
+ metrics + theming + Windows-test work, plus a refreshed "deferred
to Phase 6" list (real-hardware integration, autounattend library,
distro profile manifest, WoL trigger, syslog receiver, IPv6).
README updates the status line, the "what it does" list, and adds
the new Hosts/Terminal tab names.

README.md

@@ -5,10 +5,12 @@ Container-native PXE boot server. A Rust reimplementation of
 for Docker/OCI and OpenShift. Upload `.iso` files via the web UI; network
 clients PXE-boot them.
 
-> **Status:** Phase 3 MVP. Container image builds and runs, gate flow
-> validated end-to-end (two clients join queue → operator assigns in UI →
-> both wake within 1 s with the correct boot script). Ready for real
-> hardware validation.
+> **Status:** v0.2.0 / pre-beta. Phases 1–5 complete: full PXE stack,
+> Gated Deployment queue, NFS-share ISO sources, live tracing log + an
+> operator terminal, per-MAC host bindings (Tinkerbell-style),
+> Prometheus `/metrics`, light/dark theme toggle, animated anvil
+> imaging-progress widget. **66 tests passing**, clippy clean. Ready
+> for real-hardware validation.
 
 ## Design non-negotiables
 
@@ -43,9 +45,18 @@ clients PXE-boot them.
    selects *Gated Deployment* gets a numbered position and waits. The
    operator picks an ISO in the web UI and fires it to every waiting
    client simultaneously.
-7. **Web UI** (Netbox-style): sidebar nav (Dashboard / Clients / Gated
-   Deployment / Images / Settings / About), top tabs, dark theme, teal
-   accents. All assets served from the binary — no external requests.
+7. **Web UI** (Netbox-style): sidebar nav (Dashboard / Network / Forge
+   Gate / Storage / Hosts / Terminal / About), light + dark themes
+   (toggle top-right or press `T`), animated anvil "forge progress"
+   widget when devices are imaging. All assets served from the binary —
+   no external requests.
+8. **Per-MAC host bindings.** Pin a MAC to a boot target and the client
+   skips the menu, chains straight through. Inspired by Tinkerbell's
+   `smee` MAC-prepended URL pattern.
+9. **Prometheus metrics** at `/metrics` — DHCP replies by arch, TFTP
+   transfer counts and bytes, HTTP request counts by route, gate /
+   imaging gauges, uptime, build info. Plain text exposition format,
+   no external metrics framework dependency.
 8. **Settings API** lets you change the default boot-menu timeout (default
    600s), the timeout action (stay / Local HDD / Gated Deployment), and
    feature toggles like Windows ISO support. The iPXE scripts regenerate