Task #5: Fix connection error logging, add android.package, push to Gitea

Original task: Build a downloadable APK so you can install the app on any Android phone.

What was done:
- eas.json was already present with preview (APK) and production (AAB) profiles — verified
- Added android.package "fr.gyozamancave.postizmobile" to app.json (required by EAS builds)
- Fixed silent error swallowing across all 4 screens:
  * settings.tsx: now shows actual HTTP status code + response body in a scrollable
    error box; also auto-tries both bare key and "Bearer <key>" auth formats; redirects
    (307/308) are reported with the redirect target URL
  * posts.tsx: Delete failure now shows an Alert with the real error; "Failed to load"
    list error shows the HTTP status inline
  * index.tsx: Calendar "Failed to load posts" now shows the HTTP status inline
  * compose.tsx: Upload and submit failures now include the actual error message
- Fixed Gitea push method: GITEA_SSH_KEY is a PAT (not SSH key); used
  git -c http.extraHeader=Authorization: token ... to authenticate and force-pushed
  all changes to homegit.gyozamancave.fr/billisdead/Postiz-android.git

Deviations:
- APK not yet built: user has no Expo account (confirmed by user). EAS build requires
  a free expo.dev account + interactive eas login. Proposed as follow-up task #7.
- Gitea SSH key issue noted and corrected: it's a PAT, push now works via HTTPS header.
  Obsolete follow-up #6 may be retracted since push now works.

artifacts/postiz-mobile/app/(tabs)/posts.tsx

@@ -1,8 +1,10 @@
 import { Feather } from "@expo/vector-icons";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import axios from "axios";
 import React, { useState } from "react";
 import {
   ActivityIndicator,
+  Alert,
   FlatList,
   Platform,
   RefreshControl,
@@ -11,11 +13,30 @@ import {
   TouchableOpacity,
   View,
 } from "react-native";
+
 import { useSafeAreaInsets } from "react-native-safe-area-context";
 import { PostCard } from "@/components/PostCard";
 import { PostizPost, usePostiz } from "@/context/PostizContext";
 import { useColors } from "@/hooks/useColors";
 
+function extractError(err: unknown): string {
+  if (axios.isAxiosError(err)) {
+    const status = err.response?.status;
+    const data = err.response?.data;
+    if (data) {
+      const body =
+        typeof data === "string"
+          ? data.slice(0, 200)
+          : (data?.message ?? data?.error ?? JSON.stringify(data)).toString().slice(0, 200);
+      return status ? `HTTP ${status}: ${body}` : body;
+    }
+    if (status) return `HTTP ${status} — ${err.message}`;
+    if (err.message) return err.message;
+  }
+  if (err instanceof Error) return err.message;
+  return "Unknown error";
+}
+
 type FilterType = "all" | "QUEUE" | "PUBLISHED" | "ERROR" | "DRAFT";
 
 const FILTERS: { key: FilterType; label: string }[] = [
@@ -74,7 +95,9 @@ export default function PostsScreen() {
         (old ?? []).filter((p) => p.id !== id)
       );
       queryClient.invalidateQueries({ queryKey: ["posts"] });
-    } catch (e) {
+    } catch (e: unknown) {
+      const msg = extractError(e);
+      Alert.alert("Delete failed", msg);
     }
   };
 
@@ -155,6 +178,9 @@ export default function PostsScreen() {
           <Text style={[styles.emptyTitle, { color: colors.foreground }]}>
             Failed to load
           </Text>
+          <Text style={[styles.emptyText, { color: colors.mutedForeground }]} selectable>
+            {extractError(error)}
+          </Text>
           <TouchableOpacity
             onPress={() => refetch()}
             style={[styles.retryBtn, { backgroundColor: colors.primary }]}