feat: Cache repository configurations in frontend (#254)

Implement localStorage-based caching for repository configurations
on the main page ('src/app/page.tsx').

This feature enables the application to remember user-specified
settings for a given repository URL. When a user submits a
repository URL along with configurations such as wiki language,
wiki type, model provider, model selection, custom model options,
and advanced exclusion paths/files, these settings are now cached
locally in the browser's localStorage.

If the user later inputs the same repository URL, the previously
saved settings are automatically loaded and pre-filled in the
configuration modal. This significantly improves user experience
by reducing repetitive data entry for frequently used repositories.

The following configuration items are cached:
- Wiki Language
- Wiki Type (Comprehensive/Concise)
- Model Provider
- Model Selection
- Custom Model (boolean flag and name)
- Selected Platform (GitHub, GitLab, Bitbucket)
- Excluded Directories
- Excluded Files
- Included Directories
- Included Files

Access tokens and other sensitive information are intentionally not
cached to maintain security.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: chouzz

src/app/page.tsx

@@ -77,6 +77,50 @@ export default function Home() {
 
   const [repositoryInput, setRepositoryInput] = useState('https://github.com/AsyncFuncAI/deepwiki-open');
 
+  const REPO_CONFIG_CACHE_KEY = 'deepwikiRepoConfigCache';
+
+  const loadConfigFromCache = (repoUrl: string) => {
+    if (!repoUrl) return;
+    try {
+      const cachedConfigs = localStorage.getItem(REPO_CONFIG_CACHE_KEY);
+      if (cachedConfigs) {
+        const configs = JSON.parse(cachedConfigs);
+        const config = configs[repoUrl.trim()];
+        if (config) {
+          setSelectedLanguage(config.selectedLanguage || language);
+          setIsComprehensiveView(config.isComprehensiveView === undefined ? true : config.isComprehensiveView);
+          setProvider(config.provider || '');
+          setModel(config.model || '');
+          setIsCustomModel(config.isCustomModel || false);
+          setCustomModel(config.customModel || '');
+          setSelectedPlatform(config.selectedPlatform || 'github');
+          setExcludedDirs(config.excludedDirs || '');
+          setExcludedFiles(config.excludedFiles || '');
+          setIncludedDirs(config.includedDirs || '');
+          setIncludedFiles(config.includedFiles || '');
+        }
+      }
+    } catch (error) {
+      console.error('Error loading config from localStorage:', error);
+    }
+  };
+
+  const handleRepositoryInputChange = (e: React.ChangeEvent<HTMLInputElement>) => {
+    const newRepoUrl = e.target.value;
+    setRepositoryInput(newRepoUrl);
+    if (newRepoUrl.trim() === "") {
+      // Optionally reset fields if input is cleared
+    } else {
+        loadConfigFromCache(newRepoUrl);
+    }
+  };
+
+  useEffect(() => {
+    if (repositoryInput) {
+      loadConfigFromCache(repositoryInput);
+    }
+  }, []);
+
   // Provider-based model selection state
   const [provider, setProvider] = useState<string>('');
   const [model, setModel] = useState<string>('');
@@ -262,6 +306,30 @@ export default function Home() {
       return;
     }
 
+    try {
+      const currentRepoUrl = repositoryInput.trim();
+      if (currentRepoUrl) {
+        const existingConfigs = JSON.parse(localStorage.getItem(REPO_CONFIG_CACHE_KEY) || '{}');
+        const configToSave = {
+          selectedLanguage,
+          isComprehensiveView,
+          provider,
+          model,
+          isCustomModel,
+          customModel,
+          selectedPlatform,
+          excludedDirs,
+          excludedFiles,
+          includedDirs,
+          includedFiles,
+        };
+        existingConfigs[currentRepoUrl] = configToSave;
+        localStorage.setItem(REPO_CONFIG_CACHE_KEY, JSON.stringify(existingConfigs));
+      }
+    } catch (error) {
+      console.error('Error saving config to localStorage:', error);
+    }
+
     setIsSubmitting(true);
 
     // Parse repository input
@@ -352,7 +420,7 @@ export default function Home() {
                 <input
                   type="text"
                   value={repositoryInput}
-                  onChange={(e) => setRepositoryInput(e.target.value)}
+                  onChange={handleRepositoryInputChange}
                   placeholder={t('form.repoPlaceholder') || "owner/repo, GitHub/GitLab/BitBucket URL, or local folder path"}
                   className="input-japanese block w-full pl-10 pr-3 py-2.5 border-[var(--border-color)] rounded-lg bg-transparent text-[var(--foreground)] focus:outline-none focus:border-[var(--accent-primary)]"
                 />