style: fix btn-primary and xterm theming for dark/light mode

Use var(--bg) for btn-primary text color and color-mix for hover to
correctly adapt across themes. Add --terminal-bg CSS variable and
_getXtermTheme() helper so the SSH terminal picks up the correct
palette at connection time.

extension/dashboard/dashboard.css

@@ -26,6 +26,7 @@
       --radius-lg: 14px;
       --sidebar-w: 224px;
       --transition: 0.15s ease;
+      --terminal-bg: #0d0d0f;
     }
 
     [data-theme="light"] {
@@ -49,6 +50,7 @@
       --red:       #e11d48;
       --red-dim:   rgba(225,29,72,.10);
       --red-mid:   rgba(225,29,72,.20);
+      --terminal-bg: #1a1a1e;
     }
 
     /* Light theme: white checkmark on the darker cyan */
@@ -294,8 +296,8 @@
     .btn svg { width: 14px; height: 14px; flex-shrink: 0; }
     .btn:disabled { opacity: 0.45; cursor: not-allowed; pointer-events: none; }
 
-    .btn-primary { background: var(--cyan); color: #09090b; }
-    .btn-primary:hover { background: #06b6d4; }
+    .btn-primary { background: var(--cyan); color: var(--bg); }
+    .btn-primary:hover { background: color-mix(in srgb, var(--cyan) 85%, black); }
 
     .btn-secondary {
       background: var(--elevated);
@@ -987,7 +989,7 @@
     .terminal-statusbar span { color: var(--text3); }
     #terminalContainer {
       flex: 1;
-      background: #0d0d0f;
+      background: var(--terminal-bg);
       overflow: hidden;
       padding: 8px;
     }

extension/dashboard/pages/ssh.js

@@ -156,6 +156,58 @@ function updateTermSizeDisplay(term) {
  * @param {object} conn - SSH connection object with `hsUrl`, `username`, `password`, etc.
  * @returns {Promise<void>}
  */
+function _getXtermTheme() {
+  const isLight = document.documentElement.getAttribute('data-theme') === 'light';
+  if (isLight) {
+    return {
+      background: '#1a1a1e',
+      foreground: '#e4e4e7',
+      cursor: '#0891b2',
+      cursorAccent: '#1a1a1e',
+      selectionBackground: 'rgba(8,145,178,0.30)',
+      black: '#18181b',
+      red: '#e11d48',
+      green: '#16a34a',
+      yellow: '#d97706',
+      blue: '#2563eb',
+      magenta: '#9333ea',
+      cyan: '#0891b2',
+      white: '#e4e4e7',
+      brightBlack: '#3f3f46',
+      brightRed: '#fb7185',
+      brightGreen: '#86efac',
+      brightYellow: '#fde68a',
+      brightBlue: '#93c5fd',
+      brightMagenta: '#d8b4fe',
+      brightCyan: '#67e8f9',
+      brightWhite: '#fafafa',
+    };
+  }
+  return {
+    background: '#0d0d0f',
+    foreground: '#e4e4e7',
+    cursor: '#22d3ee',
+    cursorAccent: '#0d0d0f',
+    selectionBackground: 'rgba(34,211,238,0.25)',
+    black: '#18181b',
+    red: '#f43f5e',
+    green: '#4ade80',
+    yellow: '#fbbf24',
+    blue: '#60a5fa',
+    magenta: '#c084fc',
+    cyan: '#22d3ee',
+    white: '#e4e4e7',
+    brightBlack: '#3f3f46',
+    brightRed: '#fb7185',
+    brightGreen: '#86efac',
+    brightYellow: '#fde68a',
+    brightBlue: '#93c5fd',
+    brightMagenta: '#d8b4fe',
+    brightCyan: '#67e8f9',
+    brightWhite: '#fafafa',
+  };
+}
+
 async function connectSsh(conn) {
   if (_sshConnecting) return;
   _sshConnecting = true;
@@ -184,29 +236,7 @@ async function _connectSshImpl(conn) {
     cursorBlink: true,
     cursorStyle: 'block',
     scrollback: 5000,
-    theme: {
-      background: '#0d0d0f',
-      foreground: '#e4e4e7',
-      cursor: '#22d3ee',
-      cursorAccent: '#0d0d0f',
-      selectionBackground: 'rgba(34,211,238,0.25)',
-      black: '#18181b',
-      red: '#f43f5e',
-      green: '#4ade80',
-      yellow: '#fbbf24',
-      blue: '#60a5fa',
-      magenta: '#c084fc',
-      cyan: '#22d3ee',
-      white: '#e4e4e7',
-      brightBlack: '#3f3f46',
-      brightRed: '#fb7185',
-      brightGreen: '#86efac',
-      brightYellow: '#fde68a',
-      brightBlue: '#93c5fd',
-      brightMagenta: '#d8b4fe',
-      brightCyan: '#67e8f9',
-      brightWhite: '#fafafa'
-    }
+    theme: _getXtermTheme()
   });
 
   const fitAddon = new FitAddon.FitAddon();