Initial commit: RR3 APK Modification Tools

- Automated PowerShell script (RR3-Community-Mod.ps1)
- Complete modification guide (14,000 words)
- Quick reference summary (12,000 words)
- Network protocol analysis (13,000 words)
- One-command APK modification
- Built-in custom server support discovery

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.gitignore

@@ -0,0 +1,14 @@
+*.db
+*.db-shm
+*.db-wal
+bin/
+obj/
+.vs/
+*.user
+*.suo
+output/
+tools/
+rr3-modified/
+rr3-modified-signed.apk
+*.apk
+!realracing3.apk