feat(ui): terminal, charts and low-contrast text follow the selected theme

- The lane terminal (xterm) takes its palette from the selected DARK theme —
  it stays dark in light mode, as a terminal should — and repaints live when
  the theme changes (`client/src/lib/terminalTheme.ts`).
- Charts on the Dashboard and Workflows pages draw their grid, axes, labels
  and tooltips from theme tokens instead of hardcoded near-black/white, and
  the activity heatmap ramps from the page surface to the accent, so it reads
  on every theme instead of going near-black on light ones.
- Status/brand text that only worked on dark backgrounds
  (`text-*-300/400`) gets a darker light-mode shade (`text-*-700
  dark:text-*-300`) across sessions, conversations, workflows, config and
  settings. Categorical chart colours are kept.

client/src/components/run/TerminalView.tsx

@@ -9,13 +9,17 @@
  * The socket auto-reconnects: a server restart kills the attach PTY, and
  * without a retry the pane silently freezes on its last painted frame — it
  * still LOOKS live, but no keystroke or mouse report reaches tmux again.
+ * Always painted dark, in the palette of the user's chosen DARK theme
+ * (`lib/terminalTheme.ts`), recoloured live without re-attaching.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
-import { useEffect, useRef } from "react";
+import { useEffect, useMemo, useRef } from "react";
 import { Terminal } from "@xterm/xterm";
 import { FitAddon } from "@xterm/addon-fit";
 import { CanvasAddon } from "@xterm/addon-canvas";
 import "@xterm/xterm/css/xterm.css";
+import { useTheme } from "../../hooks/useTheme";
+import { terminalThemeFor } from "../../lib/terminalTheme";
 
 interface TerminalViewProps {
   runId: string;
@@ -33,6 +37,14 @@ export function TerminalView({ runId, wsBaseUrl, onExit }: TerminalViewProps) {
   // re-attach on each one.
   const onExitRef = useRef(onExit);
   onExitRef.current = onExit;
+  // Always the DARK theme's palette, even in light mode: Claude Code's TUI
+  // assumes a dark background. Read through a ref at construction so a theme
+  // change never re-runs the attach effect; the effect below recolours live.
+  const darkTheme = useTheme().themeFor.dark;
+  const palette = useMemo(() => terminalThemeFor(darkTheme), [darkTheme]);
+  const paletteRef = useRef(palette);
+  paletteRef.current = palette;
+  const termRef = useRef<Terminal | null>(null);
 
   useEffect(() => {
     // An explicit fontFamily pins every glyph to one bundled webfont. Left
@@ -56,7 +68,9 @@ export function TerminalView({ runId, wsBaseUrl, onExit }: TerminalViewProps) {
       fontSize: 13,
       cursorBlink: true,
       fontFamily: '"JetBrains Mono", monospace',
+      theme: paletteRef.current,
     });
+    termRef.current = term;
     const fit = new FitAddon();
     term.loadAddon(fit);
     if (containerRef.current) term.open(containerRef.current);
@@ -225,8 +239,20 @@ export function TerminalView({ runId, wsBaseUrl, onExit }: TerminalViewProps) {
       ws?.close();
       canvas?.dispose();
       term.dispose();
+      termRef.current = null;
     };
   }, [runId, wsBaseUrl]);
 
-  return <div ref={containerRef} className="h-full w-full" data-testid="terminal-view" />;
+  useEffect(() => {
+    if (termRef.current) termRef.current.options.theme = palette;
+  }, [palette]);
+
+  return (
+    <div
+      ref={containerRef}
+      className="h-full w-full"
+      style={{ backgroundColor: palette.background }}
+      data-testid="terminal-view"
+    />
+  );
 }