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.

crates/dhcp-proxy/src/reply.rs

@@ -41,7 +41,14 @@ pub struct ReplyContext<'a> {
 pub fn decide(ctx: &ReplyContext<'_>) -> BootDirective {
     match ctx.class {
         FirmwareClass::IpxeUserClass => BootDirective::HttpScript {
-            url: format!("{}/boot.ipxe", ctx.public_base_url.trim_end_matches('/')),
+            // Pass the client's MAC in the query string so the HTTP
+            // layer can short-circuit to a per-MAC binding when one
+            // exists. iPXE substitutes `${mac}` literally before issuing
+            // the GET, so this stays static across firmwares.
+            url: format!(
+                "{}/boot.ipxe?mac=${{mac}}",
+                ctx.public_base_url.trim_end_matches('/')
+            ),
         },
         FirmwareClass::HttpClient => {
             // UEFI HTTP boot: client wants an http:// URL in option 67

crates/dhcp-proxy/src/server.rs

@@ -19,6 +19,7 @@ pub struct DhcpProxyServer {
     our_ip: Ipv4Addr,
     public_base_url: String,
     clients: Arc<ClientRegistry>,
+    metrics: pxeforge_core::Metrics,
 }
 
 impl DhcpProxyServer {
@@ -29,8 +30,17 @@ impl DhcpProxyServer {
         our_ip: Ipv4Addr,
         public_base_url: String,
         clients: Arc<ClientRegistry>,
+        metrics: pxeforge_core::Metrics,
     ) -> Self {
-        Self { bind, dhcp_port, pxe_port, our_ip, public_base_url, clients }
+        Self {
+            bind,
+            dhcp_port,
+            pxe_port,
+            our_ip,
+            public_base_url,
+            clients,
+            metrics,
+        }
     }
 
     pub async fn run(self) -> anyhow::Result<()> {
@@ -116,12 +126,14 @@ impl DhcpProxyServer {
         };
         let directive = decide(&ctx);
         if matches!(directive, BootDirective::Ignore) {
+            self.metrics.record_dhcp_decline();
             tracing::debug!(
                 target: "pxeforge::dhcp",
                 mac=%mac, arch=?arch, "ignoring — no bootfile for arch"
             );
             return Ok(());
         }
+        self.metrics.record_dhcp_reply(arch.as_str());
 
         let Some(reply) = build_reply(&ctx, &directive) else { return Ok(()); };
         let mut out = Vec::with_capacity(512);