theme config, layout preview, container alignment

Server: ThemeConfig entity + CRUD (GET/PUT /theme), SQLite persistence,
ThemeUpdate broadcast to ESP32 on save and initial connect.
Client: render engine uses theme colors, full-screen redraw on theme change.
SPA: theme page with color pickers + presets, layout preview with TS port
of layout engine, justify/align controls on containers.
DisplayHint refactored to struct (kind + h_align + v_align).

crates/client-domain/tests/markup_tests.rs

@@ -7,39 +7,73 @@ fn theme() -> ThemeConfig {
 #[test]
 fn plain_text_produces_single_span() {
     let spans = parse_markup("hello world", &theme());
-    assert_eq!(spans, vec![
-        TextSpan { text: "hello world".into(), color: theme().text },
-    ]);
+    assert_eq!(
+        spans,
+        vec![TextSpan {
+            text: "hello world".into(),
+            color: theme().text
+        },]
+    );
 }
 
 #[test]
 fn hex_color_span() {
     let spans = parse_markup("temp: {#FF0000}72°F{/}", &theme());
-    assert_eq!(spans, vec![
-        TextSpan { text: "temp: ".into(), color: theme().text },
-        TextSpan { text: "72°F".into(), color: Color(0xFF, 0, 0) },
-    ]);
+    assert_eq!(
+        spans,
+        vec![
+            TextSpan {
+                text: "temp: ".into(),
+                color: theme().text
+            },
+            TextSpan {
+                text: "72°F".into(),
+                color: Color(0xFF, 0, 0)
+            },
+        ]
+    );
 }
 
 #[test]
 fn theme_color_spans() {
     let t = theme();
     let spans = parse_markup("{primary}hello{/} {accent}world{/}", &t);
-    assert_eq!(spans, vec![
-        TextSpan { text: "hello".into(), color: t.primary },
-        TextSpan { text: " ".into(), color: t.text },
-        TextSpan { text: "world".into(), color: t.accent },
-    ]);
+    assert_eq!(
+        spans,
+        vec![
+            TextSpan {
+                text: "hello".into(),
+                color: t.primary
+            },
+            TextSpan {
+                text: " ".into(),
+                color: t.text
+            },
+            TextSpan {
+                text: "world".into(),
+                color: t.accent
+            },
+        ]
+    );
 }
 
 #[test]
 fn reset_returns_to_text_color() {
     let t = theme();
     let spans = parse_markup("{accent}hi{/}bye", &t);
-    assert_eq!(spans, vec![
-        TextSpan { text: "hi".into(), color: t.accent },
-        TextSpan { text: "bye".into(), color: t.text },
-    ]);
+    assert_eq!(
+        spans,
+        vec![
+            TextSpan {
+                text: "hi".into(),
+                color: t.accent
+            },
+            TextSpan {
+                text: "bye".into(),
+                color: t.text
+            },
+        ]
+    );
 }
 
 #[test]
@@ -52,16 +86,29 @@ fn empty_input_produces_no_spans() {
 fn adjacent_color_spans_no_text_between() {
     let t = theme();
     let spans = parse_markup("{primary}a{secondary}b{/}", &t);
-    assert_eq!(spans, vec![
-        TextSpan { text: "a".into(), color: t.primary },
-        TextSpan { text: "b".into(), color: t.secondary },
-    ]);
+    assert_eq!(
+        spans,
+        vec![
+            TextSpan {
+                text: "a".into(),
+                color: t.primary
+            },
+            TextSpan {
+                text: "b".into(),
+                color: t.secondary
+            },
+        ]
+    );
 }
 
 #[test]
 fn unknown_tag_treated_as_literal() {
     let spans = parse_markup("{unknown}text", &theme());
-    assert_eq!(spans, vec![
-        TextSpan { text: "text".into(), color: theme().text },
-    ]);
+    assert_eq!(
+        spans,
+        vec![TextSpan {
+            text: "text".into(),
+            color: theme().text
+        },]
+    );
 }