fc3g(ext): cookies extraction + FC backend API client

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

extension/lib/api.js

@@ -0,0 +1,93 @@
+/**
+ * FC backend client. Talks to /api/credentials (FC-3b), /api/sources
+ * (FC-3a), and the new /api/extension/* endpoints (FC-3g).
+ */
+
+class FabledCuratorAPI {
+  constructor() {
+    this.baseUrl = null;
+    this.apiKey = null;
+  }
+
+  async init() {
+    const cfg = await browser.storage.local.get(['apiUrl', 'apiKey']);
+    this.baseUrl = cfg.apiUrl || null;
+    this.apiKey = cfg.apiKey || null;
+    return this.isConfigured();
+  }
+
+  isConfigured() {
+    return !!(this.baseUrl && this.apiKey);
+  }
+
+  async request(method, endpoint, data = null) {
+    if (!this.isConfigured()) {
+      throw new Error('Not configured. Set FC URL + API key in settings.');
+    }
+    const url = `${this.baseUrl.replace(/\/+$/, '')}${endpoint}`;
+    const options = {
+      method,
+      headers: {
+        'Content-Type': 'application/json',
+        'X-Extension-Key': this.apiKey,
+      },
+    };
+    if (data) options.body = JSON.stringify(data);
+
+    let response;
+    try {
+      response = await fetch(url, options);
+    } catch (e) {
+      throw new Error('Cannot connect to FabledCurator. Check URL.');
+    }
+
+    if (!response.ok) {
+      let message;
+      try {
+        const body = await response.json();
+        message = body.error || `HTTP ${response.status}`;
+        if (body.detail) message += `: ${body.detail}`;
+      } catch {
+        message = `HTTP ${response.status}: ${response.statusText}`;
+      }
+      const err = new Error(message);
+      err.status = response.status;
+      throw err;
+    }
+
+    if (response.status === 204) return { success: true };
+    return response.json();
+  }
+
+  // FC-3b — credentials.
+  uploadCredentials(platform, credentialType, data) {
+    return this.request('POST', '/credentials', {
+      platform,
+      credential_type: credentialType,
+      data,
+    });
+  }
+  getCredentials() {
+    return this.request('GET', '/credentials');
+  }
+
+  // FC-3a — sources.
+  listSources() {
+    return this.request('GET', '/sources');
+  }
+  triggerSourceCheck(sourceId) {
+    return this.request('POST', `/sources/${sourceId}/check`);
+  }
+
+  // FC-3g — extension-specific.
+  quickAddSource(url) {
+    return this.request('POST', '/extension/quick-add-source', { url });
+  }
+
+  // Connection test = the cheapest read with auth.
+  testConnection() {
+    return this.request('GET', '/credentials');
+  }
+}
+
+const api = new FabledCuratorAPI();