Initial import of fitme3070.pt platform

Plain-PHP fleet platform with id.andmore.pt SSO. Wires shared/platform-tools
as a submodule (platform_update, backups, git/migration tools) like the other
platforms.

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

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "shared/platform-tools"]
+	path = shared/platform-tools
+	url = http://192.168.1.3:30008/andre/platform-tools.git