Add dimmed viewing mode via minimize button

- Minimize button now toggles a comfortable viewing filter
- Applies brightness(0.5) contrast(1.25) sepia(0.6)
- Smooth 0.3s transition between modes
- Persists choice in localStorage
- Creates warm, dimmed aesthetic while keeping XP theme

Click minimize to toggle between bright and dimmed modes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

static/app.js

@@ -1,4 +1,35 @@
 (() => {
+  // Dim mode toggle (minimize button)
+  const minimizeBtn = document.getElementById("minimizeBtn");
+
+  function getDimMode() {
+    return localStorage.getItem("dim-mode") === "true";
+  }
+
+  function setDimMode(enabled) {
+    if (enabled) {
+      document.body.classList.add("dimmed");
+    } else {
+      document.body.classList.remove("dimmed");
+    }
+    localStorage.setItem("dim-mode", enabled.toString());
+  }
+
+  function toggleDimMode() {
+    const current = document.body.classList.contains("dimmed");
+    setDimMode(!current);
+  }
+
+  // Initialize dim mode
+  if (getDimMode()) {
+    document.body.classList.add("dimmed");
+  }
+
+  // Listen for minimize button click
+  if (minimizeBtn) {
+    minimizeBtn.addEventListener("click", toggleDimMode);
+  }
+
   let qs = new URLSearchParams(window.location.search);
   const qInput = document.getElementById("q");
   const channelDropdown = document.getElementById("channelDropdown");