chore: bump version to 0.7.1 + v0.7.1 release notes

Bumps Cargo.toml + tauri.conf.json + android tauri.properties
(versionCode 7000 → 7001). v0.7.1 = UI polish + bug-fix pass on
v0.7.0, wire-compatible.

download.html: new v0.7.1 section at top with detailed bullets for:
- Friend button (follow+vouch)
- Default visibility = Extended Friends (FoF)
- Network Identity → Device Address rename
- Settings persona/device clarity
- Profile-display-name bug fix
- Redundancy panel author-query fix
- My Posts horizontal-scroll regression fix

v0.7.0 entry retained below with full original release notes.

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

crates/tauri-app/tauri.conf.json

@@ -1,6 +1,6 @@
 {
   "productName": "itsgoin",
-  "version": "0.7.0",
+  "version": "0.7.1",
   "identifier": "com.itsgoin.app",
   "build": {
     "frontendDist": "../../frontend",