v0.4.1: harden ISO uploads and beta UI polish

Add browser-safe chunked ISO uploads with progress, partial-file visibility, offset validation, and abort cleanup while keeping the legacy multipart endpoint for API clients.

Record host-log validation coverage, keep the queue/status UI copy clean, move release docs to 0.4.1, and tighten the dark theme to a near-black Netbox-style palette.

crates/http-api/src/state.rs

@@ -1,3 +1,4 @@
+use crate::uploads::UploadSessions;
 use openpxe_core::{
     BootLog, ClientRegistry, DeploymentQueue, HostBindings, LogBus, Metrics, SettingsStore,
 };
@@ -31,6 +32,10 @@ pub struct AppState {
     /// available in the runtime image. Surfaces errors per-mount rather
     /// than failing the global state.
     pub nfs: NfsManager,
+    /// Browser chunked upload state. Multipart uploads still go straight
+    /// through `IsoStore`, but the UI uses sessions so large ISO transfers
+    /// can show deterministic progress and leave visible partial files.
+    pub uploads: UploadSessions,
     /// Live log bus consumed by the Terminal tab via SSE. Operator-issued
     /// terminal commands also push synthetic lines onto it so the tail
     /// shows them inline.