feat: Make semantic search optional and disabled by default

- Add SemanticSearchConfig interface with enabled toggle to siteConfig.ts
- Default semantic search to disabled (enabled: false) to avoid blocking forks without OPENAI_API_KEY
- Update SearchModal.tsx to conditionally show mode toggle based on config
- Update sync-posts.ts to skip embedding generation when disabled
- Add semantic search toggle to Dashboard config generator
- Update FORK_CONFIG.md with Semantic Search Configuration section
- Update fork-config.json.example with semanticSearch option
- Update docs-semantic-search.md with enable/disable instructions
- Update changelog and documentation

When disabled (default):
- Search modal shows only keyword search (no mode toggle)
- Embedding generation skipped during sync
- No OpenAI API key required

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/SearchModal.tsx

@@ -11,6 +11,7 @@ import {
   TextAa,
   Brain,
 } from "@phosphor-icons/react";
+import { siteConfig } from "../config/siteConfig";
 
 interface SearchModalProps {
   isOpen: boolean;
@@ -31,6 +32,9 @@ interface SearchResult {
 }
 
 export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
+  // Check if semantic search is enabled in siteConfig
+  const semanticEnabled = siteConfig.semanticSearch?.enabled !== false;
+
   const [searchQuery, setSearchQuery] = useState("");
   const [selectedIndex, setSelectedIndex] = useState(0);
   const [searchMode, setSearchMode] = useState<SearchMode>("keyword");
@@ -100,8 +104,8 @@ export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
   // Handle keyboard navigation
   const handleKeyDown = useCallback(
     (e: React.KeyboardEvent) => {
-      // Tab toggles between search modes
-      if (e.key === "Tab") {
+      // Tab toggles between search modes (only if semantic search is enabled)
+      if (e.key === "Tab" && semanticEnabled) {
         e.preventDefault();
         setSearchMode((prev) => (prev === "keyword" ? "semantic" : "keyword"));
         return;
@@ -142,7 +146,7 @@ export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
           break;
       }
     },
-    [results, selectedIndex, navigate, onClose, searchMode, searchQuery]
+    [results, selectedIndex, navigate, onClose, searchMode, searchQuery, semanticEnabled]
   );
 
   // Handle clicking on a result
@@ -168,25 +172,27 @@ export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
   return (
     <div className="search-modal-backdrop" onClick={handleBackdropClick}>
       <div className="search-modal">
-        {/* Search mode toggle */}
-        <div className="search-mode-toggle">
-          <button
-            className={`search-mode-btn ${searchMode === "keyword" ? "active" : ""}`}
-            onClick={() => setSearchMode("keyword")}
-            title="Keyword search - matches exact words"
-          >
-            <TextAa size={16} weight="bold" />
-            <span>Keyword</span>
-          </button>
-          <button
-            className={`search-mode-btn ${searchMode === "semantic" ? "active" : ""}`}
-            onClick={() => setSearchMode("semantic")}
-            title="Semantic search - finds similar meaning"
-          >
-            <Brain size={16} weight="bold" />
-            <span>Semantic</span>
-          </button>
-        </div>
+        {/* Search mode toggle - only shown when semantic search is enabled */}
+        {semanticEnabled && (
+          <div className="search-mode-toggle">
+            <button
+              className={`search-mode-btn ${searchMode === "keyword" ? "active" : ""}`}
+              onClick={() => setSearchMode("keyword")}
+              title="Keyword search - matches exact words"
+            >
+              <TextAa size={16} weight="bold" />
+              <span>Keyword</span>
+            </button>
+            <button
+              className={`search-mode-btn ${searchMode === "semantic" ? "active" : ""}`}
+              onClick={() => setSearchMode("semantic")}
+              title="Semantic search - finds similar meaning"
+            >
+              <Brain size={16} weight="bold" />
+              <span>Semantic</span>
+            </button>
+          </div>
+        )}
 
         {/* Search input */}
         <div className="search-modal-input-wrapper">
@@ -223,9 +229,11 @@ export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
                   : "Describe what you're looking for"}
               </p>
               <div className="search-modal-shortcuts">
-                <span className="search-shortcut">
-                  <kbd>Tab</kbd> Switch mode
-                </span>
+                {semanticEnabled && (
+                  <span className="search-shortcut">
+                    <kbd>Tab</kbd> Switch mode
+                  </span>
+                )}
                 <span className="search-shortcut">
                   <kbd>↑</kbd>
                   <kbd>↓</kbd> Navigate
@@ -292,9 +300,11 @@ export default function SearchModal({ isOpen, onClose }: SearchModalProps) {
         {/* Footer with keyboard hints */}
         {results && results.length > 0 && (
           <div className="search-modal-footer">
-            <span className="search-footer-hint">
-              <kbd>Tab</kbd> switch mode
-            </span>
+            {semanticEnabled && (
+              <span className="search-footer-hint">
+                <kbd>Tab</kbd> switch mode
+              </span>
+            )}
             <span className="search-footer-hint">
               <kbd>↵</kbd> select
             </span>

src/config/siteConfig.ts

@@ -236,6 +236,13 @@ export interface ImageLightboxConfig {
   enabled: boolean; // Global toggle for image lightbox feature
 }
 
+// Semantic search configuration
+// Enables AI-powered search using vector embeddings
+// Requires OPENAI_API_KEY environment variable in Convex dashboard
+export interface SemanticSearchConfig {
+  enabled: boolean; // Global toggle for semantic search feature
+}
+
 // Social link configuration for social footer
 export interface SocialLink {
   platform:
@@ -365,6 +372,9 @@ export interface SiteConfig {
 
   // AI Dashboard configuration (optional)
   aiDashboard?: AIDashboardConfig;
+
+  // Semantic search configuration (optional)
+  semanticSearch?: SemanticSearchConfig;
 }
 
 // Default site configuration
@@ -744,6 +754,13 @@ export const siteConfig: SiteConfig = {
       },
     ],
   },
+
+  // Semantic search configuration
+  // Set enabled: true to enable semantic search (requires OPENAI_API_KEY in Convex)
+  // When disabled, only keyword search is available (no API key needed)
+  semanticSearch: {
+    enabled: false, // Set to true to enable semantic search (requires OPENAI_API_KEY)
+  },
 };
 
 // Export the config as default for easy importing

src/pages/Dashboard.tsx

@@ -4597,6 +4597,8 @@ function ConfigSection({
     mcpServerRequireAuth: siteConfig.mcpServer?.requireAuth || false,
     // Image lightbox
     imageLightboxEnabled: siteConfig.imageLightbox?.enabled !== false,
+    // Semantic search
+    semanticSearchEnabled: siteConfig.semanticSearch?.enabled || false,
   });
 
   const [copied, setCopied] = useState(false);
@@ -4762,6 +4764,12 @@ export const siteConfig: SiteConfig = {
   imageLightbox: {
     enabled: ${config.imageLightboxEnabled},
   },
+
+  // Semantic search configuration
+  // Set enabled: true to enable AI-powered semantic search (requires OPENAI_API_KEY in Convex)
+  semanticSearch: {
+    enabled: ${config.semanticSearchEnabled},
+  },
 };
 
 export default siteConfig;
@@ -5573,6 +5581,26 @@ export default siteConfig;
           </div>
         </div>
 
+        {/* Semantic Search */}
+        <div className="dashboard-config-card">
+          <h3>Semantic Search</h3>
+          <div className="config-field checkbox">
+            <label>
+              <input
+                type="checkbox"
+                checked={config.semanticSearchEnabled}
+                onChange={(e) =>
+                  handleChange("semanticSearchEnabled", e.target.checked)
+                }
+              />
+              <span>Enable semantic search (requires OPENAI_API_KEY in Convex)</span>
+            </label>
+          </div>
+          <p className="config-hint">
+            When enabled, search modal shows both Keyword and Semantic modes. Requires OpenAI API key for embeddings.
+          </p>
+        </div>
+
         {/* Links */}
         <div className="dashboard-config-card">
           <h3>External Links</h3>