release(fdroid): v0.4.3 — fix self-hosted F-Droid publish (v2-only signing)

The self-hosted F-Droid repo (https://dzianisv.github.io/opencode-mobile/fdroid/repo)
has been stuck at v0.4.1 because publish-fdroid crashed in androguard parsing the
CI APK's v2+v3 signature block pair ('NoOverwriteDict' object has no attribute
'append'). Force v1+v2-only signing: gradle flags for local builds, plus a
deterministic apksigner re-sign step in the workflow (expo prebuild regenerates
build.gradle, so the workflow step is the real guarantee). Bump to v0.4.3 /
versionCode 5 so a fresh tag re-runs the publish with the verified bug fixes
(#10 scope fixes, send-error fix) included.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@opencode-ai/mobile",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "private": true,
   "main": "expo-router/entry",
   "scripts": {