chore: bump retrofit from 2.11.0 to 3.0.0 (#382)

Bump Retrofit 2.11.0 → 3.0.0. Forward binary-compatible — same package (retrofit2.*), same API surface, zero code changes needed.

gradle/libs.versions.toml

@@ -20,7 +20,7 @@ nav3Core = "1.0.1"
 lifecycleViewmodelNav3 = "2.10.0"
 leakcanary = "2.14"
 okhttp = "5.4.0"
-retrofit = "2.11.0"
+retrofit = "3.0.0"
 gson = "2.14.0"
 securityCrypto = "1.0.0"
 mockk = "1.14.11"