feat: UX improvements, security hardening, and code cleanup

- Extract shared extractError utility (lib/extractError.ts), remove 3 duplicate copies
- Export DEFAULT_BASE_URL from PostizContext, remove duplicate in settings
- Add 401 interceptor in axios client: fires UnauthorizedHandler in _layout → alert + redirect to Settings
- Calendar day items now tappable: tap opens context menu (Copy / Edit / Repost)
- Persist sort order (newest/oldest) across sessions via AsyncStorage
- Filter chips show post count per status (Queue 3, Error 1, etc.)
- Copy text action now shows a brief "Copied" toast + haptic feedback
- PostCard: swipe right → Reschedule action (QUEUE posts only, amber color)
- Compose: per-network char limit (Twitter 280, Instagram 2200…) with color warning at 90%
- Compose: local draft save/restore via AsyncStorage with restore banner on open
- Compose: prefillImagePath/prefillImageId params allow Edit/Repost to carry over existing media

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

artifacts/postiz-mobile/context/PostizContext.tsx

@@ -5,12 +5,13 @@ import React, {
   useCallback,
   useContext,
   useEffect,
+  useRef,
   useState,
 } from "react";
 
 const API_KEY_STORAGE = "postiz_api_key";
 const BASE_URL_STORAGE = "postiz_base_url";
-const DEFAULT_BASE_URL = "https://postiz.gyozamancave.fr/api/public/v1";
+export const DEFAULT_BASE_URL = "https://postiz.gyozamancave.fr/api/public/v1";
 
 export interface PostizIntegration {
   id: string;
@@ -48,6 +49,8 @@ interface PostizContextValue {
   baseUrl: string;
   isConfigured: boolean;
   isLoading: boolean;
+  unauthorized: boolean;
+  clearUnauthorized: () => void;
   client: AxiosInstance | null;
   saveSettings: (apiKey: string, baseUrl: string) => Promise<void>;
   clearSettings: () => Promise<void>;
@@ -58,12 +61,18 @@ const PostizContext = createContext<PostizContextValue>({
   baseUrl: DEFAULT_BASE_URL,
   isConfigured: false,
   isLoading: true,
+  unauthorized: false,
+  clearUnauthorized: () => {},
   client: null,
   saveSettings: async () => {},
   clearSettings: async () => {},
 });
 
-function createClient(apiKey: string, baseUrl: string): AxiosInstance {
+function createClient(
+  apiKey: string,
+  baseUrl: string,
+  onUnauthorized?: () => void
+): AxiosInstance {
   const normalizedUrl = baseUrl.endsWith("/") ? baseUrl : baseUrl + "/";
   const instance = axios.create({
     baseURL: normalizedUrl,
@@ -77,6 +86,15 @@ function createClient(apiKey: string, baseUrl: string): AxiosInstance {
     console.log(">>> REQUEST:", config.method?.toUpperCase(), (config.baseURL || "") + (config.url || ""));
     return config;
   });
+  instance.interceptors.response.use(
+    (res) => res,
+    (err) => {
+      if (axios.isAxiosError(err) && err.response?.status === 401) {
+        onUnauthorized?.();
+      }
+      return Promise.reject(err);
+    }
+  );
   return instance;
 }
 
@@ -85,6 +103,19 @@ export function PostizProvider({ children }: { children: React.ReactNode }) {
   const [baseUrl, setBaseUrl] = useState(DEFAULT_BASE_URL);
   const [isLoading, setIsLoading] = useState(true);
   const [client, setClient] = useState<AxiosInstance | null>(null);
+  const [unauthorized, setUnauthorized] = useState(false);
+  const unauthorizedFiredRef = useRef(false);
+
+  const handleUnauthorized = useCallback(() => {
+    if (unauthorizedFiredRef.current) return;
+    unauthorizedFiredRef.current = true;
+    setUnauthorized(true);
+  }, []);
+
+  const clearUnauthorized = useCallback(() => {
+    unauthorizedFiredRef.current = false;
+    setUnauthorized(false);
+  }, []);
 
   useEffect(() => {
     (async () => {
@@ -95,14 +126,14 @@ export function PostizProvider({ children }: { children: React.ReactNode }) {
           const url = (storedUrl || DEFAULT_BASE_URL).replace(/\/$/, "");
           setApiKey(storedKey);
           setBaseUrl(url);
-          setClient(() => createClient(storedKey, url));
+          setClient(() => createClient(storedKey, url, handleUnauthorized));
         }
       } catch {
       } finally {
         setIsLoading(false);
       }
     })();
-  }, []);
+  }, [handleUnauthorized]);
 
   const saveSettings = useCallback(
     async (newApiKey: string, newBaseUrl: string) => {
@@ -110,9 +141,10 @@ export function PostizProvider({ children }: { children: React.ReactNode }) {
       await SecureStore.setItemAsync(BASE_URL_STORAGE, newBaseUrl);
       setApiKey(newApiKey);
       setBaseUrl(newBaseUrl);
-      setClient(() => createClient(newApiKey, newBaseUrl));
+      clearUnauthorized();
+      setClient(() => createClient(newApiKey, newBaseUrl, handleUnauthorized));
     },
-    []
+    [handleUnauthorized, clearUnauthorized]
   );
 
   const clearSettings = useCallback(async () => {
@@ -121,7 +153,8 @@ export function PostizProvider({ children }: { children: React.ReactNode }) {
     setApiKey("");
     setBaseUrl(DEFAULT_BASE_URL);
     setClient(null);
-  }, []);
+    clearUnauthorized();
+  }, [clearUnauthorized]);
 
   return (
     <PostizContext.Provider
@@ -130,6 +163,8 @@ export function PostizProvider({ children }: { children: React.ReactNode }) {
         baseUrl,
         isConfigured: !!apiKey,
         isLoading,
+        unauthorized,
+        clearUnauthorized,
         client,
         saveSettings,
         clearSettings,