feat: Implement Gogh Theme Engine with options page, theme parsing, and semantic theme derivation

We're cooked. <skull emoji>

- Added options page for YAML palette editing, live color preview, and diagnostics.
- Implemented theme engine to parse Gogh YAML palettes and derive semantic themes.
- Configured TypeScript and Vite for building the extension.
- Created new tab and popup HTML pages with corresponding scripts and styles.
- Established storage management for user configurations in Chrome storage.
- Added icons for the extension and updated manifest for MV3 compatibility.

gogh-theme-engine/public/icons/icon.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128">
+  <rect width="128" height="128" rx="20" fill="#282a36"/>
+  <text x="64" y="80" font-family="Arial, sans-serif" font-size="64" text-anchor="middle" fill="#f8f8f2">G</text>
+  <circle cx="96" cy="32" r="12" fill="#ff79c6"/>
+  <circle cx="96" cy="32" r="6" fill="#bd93f9"/>
+</svg>

gogh-theme-engine/public/manifest.json

@@ -0,0 +1,33 @@
+{
+  "manifest_version": 3,
+  "name": "Gogh Theme Engine",
+  "version": "1.0.0",
+  "description": "Apply Gogh-style 16-color terminal palettes to any web page using perceptual OKLCH color remapping.",
+  "permissions": ["storage", "activeTab", "scripting"],
+  "background": {
+    "service_worker": "background.js",
+    "type": "module"
+  },
+  "content_scripts": [
+    {
+      "matches": ["<all_urls>"],
+      "js": ["content.js"],
+      "run_at": "document_start",
+      "all_frames": true
+    }
+  ],
+  "options_page": "options/options.html",
+  "action": {
+    "default_title": "Gogh Theme Engine",
+    "default_icon": {
+      "16": "icons/icon16.png",
+      "48": "icons/icon48.png",
+      "128": "icons/icon128.png"
+    }
+  },
+  "icons": {
+    "16": "icons/icon16.png",
+    "48": "icons/icon48.png",
+    "128": "icons/icon128.png"
+  }
+}