feat: add chat page layout with message list and bubble components

- Create /chat route with scrollable message list
- MessageBubble component with distinct user/assistant styles
- MessageList with auto-scroll-to-bottom on new messages
- Empty state display when no messages
- ChatMessage type definition in src/lib/types.ts
- Add browser globals to ESLint config for Svelte files

Closes #5

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package-lock.json

@@ -21,6 +21,7 @@
 				"eslint": "^9.0.0",
 				"eslint-config-prettier": "^10.0.0",
 				"eslint-plugin-svelte": "^3.0.0",
+				"globals": "^17.4.0",
 				"prettier": "^3.0.0",
 				"prettier-plugin-svelte": "^3.0.0",
 				"svelte": "^5.51.0",
@@ -803,6 +804,19 @@
 				"url": "https://opencollective.com/eslint"
 			}
 		},
+		"node_modules/@eslint/eslintrc/node_modules/globals": {
+			"version": "14.0.0",
+			"resolved": "https://registry.npmjs.org/globals/-/globals-14.0.0.tgz",
+			"integrity": "sha512-oahGvuMGQlPw/ivIYBjVSrWAfWLBeku5tpPE2fOPLi+WHffIWbuh2tCjhyQhTBPMf5E9jDEH4FOmTYgYwbKwtQ==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">=18"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/sindresorhus"
+			}
+		},
 		"node_modules/@eslint/js": {
 			"version": "9.39.4",
 			"resolved": "https://registry.npmjs.org/@eslint/js/-/js-9.39.4.tgz",
@@ -2695,9 +2709,9 @@
 			}
 		},
 		"node_modules/globals": {
-			"version": "14.0.0",
-			"resolved": "https://registry.npmjs.org/globals/-/globals-14.0.0.tgz",
-			"integrity": "sha512-oahGvuMGQlPw/ivIYBjVSrWAfWLBeku5tpPE2fOPLi+WHffIWbuh2tCjhyQhTBPMf5E9jDEH4FOmTYgYwbKwtQ==",
+			"version": "17.4.0",
+			"resolved": "https://registry.npmjs.org/globals/-/globals-17.4.0.tgz",
+			"integrity": "sha512-hjrNztw/VajQwOLsMNT1cbJiH2muO3OROCHnbehc8eY5JyD2gqz4AcMHPqgaOR59DjgUjYAYLeH699g/eWi2jw==",
 			"dev": true,
 			"license": "MIT",
 			"engines": {