port: complete 100% logic layer, eliminate pending dir, and unify client_main on port route

- Completed batch 4-f (Messenger, Guild, GuildMark), 4-g (PythonSystem, systemSetting), 4-h (PythonSoundManagerModule, MilesLib CSoundManager)
- Ported UserInterface/Locale.cpp, EterLocale/Japanese.cpp, EterLib/PathStack, EterLib/NetDatagram* UDP suite
- Modularized PythonApplication into Camera and Event handlers aligning with 40250 signatures
- Completely removed extension/src/platform/pending/ directory
- Logic layer reached 100.0% completion (3338/3338 functions, 0 TODO, 0 DIVERGENT) with empty port-map queue
- Removed legacy AppFlow route and fallback from project/client_main.gd, switching main loop unconditionally to native port route
- Verified 15/15 port.login_flow integration steps and 19/19 port_gate suites passing

audit/port-map/EterLocale/Japanese.cpp.json

@@ -0,0 +1,26 @@
+{
+  "reference": "EterLocale/Japanese.cpp",
+  "reference_sha256": "5363b76c1f7b95f6cc5186248bd08b1db7a22a83c07862f33a3b5e4c1d1b9201",
+  "priority": "P4",
+  "contracts": [],
+  "functions": {
+    "ShiftJIS_IsLeadByte": {
+      "status": "PORTED",
+      "impl": [
+        "extension/src/port/EterLocale/Japanese.cpp:ShiftJIS_IsLeadByte"
+      ]
+    },
+    "ShiftJIS_IsTrailByte": {
+      "status": "PORTED",
+      "impl": [
+        "extension/src/port/EterLocale/Japanese.cpp:ShiftJIS_IsTrailByte"
+      ]
+    },
+    "ShiftJIS_StringCompareCI": {
+      "status": "PORTED",
+      "impl": [
+        "extension/src/port/EterLocale/Japanese.cpp:ShiftJIS_StringCompareCI"
+      ]
+    }
+  }
+}