add SPA config UI, wire media/rss adapters, event-driven layout push

- React SPA: dashboard, data sources CRUD, widgets CRUD, layout builder,
  presets. TanStack Router + Query, shadcn/ui, Vite proxy to :3000
- wire media + rss adapters into polling loop, remove xtb source type
- media adapter: read username/password from headers, proper subsonic auth
- event handler: subscribe to LayoutChanged, push screen update to clients
- fix clippy warnings across workspace (Default impls, collapsible ifs,
  redundant closures, is_none_or, unused imports)

crates/protocol/src/wire.rs

@@ -1,9 +1,9 @@
-use std::collections::BTreeMap;
-use serde::{Serialize, Deserialize};
 use domain::value_objects::{
-    ContainerNode, Direction, DisplayHint, LayoutChild, LayoutNode, Sizing, Value,
-    WidgetError, WidgetState,
+    ContainerNode, Direction, DisplayHint, LayoutChild, LayoutNode, Sizing, Value, WidgetError,
+    WidgetState,
 };
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum WireValue {
@@ -84,10 +84,14 @@ pub struct WireWidgetState {
 impl From<&WidgetState> for WireWidgetState {
     fn from(s: &WidgetState) -> Self {
         WireWidgetState {
-            data: s.data.iter().map(|(k, v)| WireKeyValue {
-                key: k.clone(),
-                value: v.into(),
-            }).collect(),
+            data: s
+                .data
+                .iter()
+                .map(|(k, v)| WireKeyValue {
+                    key: k.clone(),
+                    value: v.into(),
+                })
+                .collect(),
             error: s.error.as_ref().map(Into::into),
         }
     }
@@ -96,7 +100,11 @@ impl From<&WidgetState> for WireWidgetState {
 impl From<WireWidgetState> for WidgetState {
     fn from(w: WireWidgetState) -> Self {
         WidgetState {
-            data: w.data.into_iter().map(|kv| (kv.key, kv.value.into())).collect(),
+            data: w
+                .data
+                .into_iter()
+                .map(|kv| (kv.key, kv.value.into()))
+                .collect(),
             error: w.error.map(Into::into),
         }
     }
@@ -205,10 +213,14 @@ impl From<&LayoutNode> for WireLayoutNode {
                 direction: (&c.direction).into(),
                 gap: c.gap,
                 padding: c.padding,
-                children: c.children.iter().map(|ch| WireLayoutChild {
-                    sizing: (&ch.sizing).into(),
-                    node: (&ch.node).into(),
-                }).collect(),
+                children: c
+                    .children
+                    .iter()
+                    .map(|ch| WireLayoutChild {
+                        sizing: (&ch.sizing).into(),
+                        node: (&ch.node).into(),
+                    })
+                    .collect(),
             }),
         }
     }
@@ -222,10 +234,14 @@ impl From<WireLayoutNode> for LayoutNode {
                 direction: c.direction.into(),
                 gap: c.gap,
                 padding: c.padding,
-                children: c.children.into_iter().map(|ch| LayoutChild {
-                    sizing: ch.sizing.into(),
-                    node: ch.node.into(),
-                }).collect(),
+                children: c
+                    .children
+                    .into_iter()
+                    .map(|ch| LayoutChild {
+                        sizing: ch.sizing.into(),
+                        node: ch.node.into(),
+                    })
+                    .collect(),
             }),
         }
     }