Add complexionFormId to appearance payload

Introduce complexionFormId (TXST) into RemoteAppearance and the appearance protocol so complexion textures are captured and serialized. Updates: header/state, Networking JSON parse/serialize, proxy actor comparisons, main capture logic, protocol docs, fake client/player samples, changelog and dev-log. Capture reads PlayerCharacter::complexion and serializes it, but applying to proxies is intentionally a no-op because TESNPC proxies lack a complexion field (documented in comments/dev-log). Files: plugin/include/F4TRemotePlayerState.h, plugin/src/*, protocol/packets.md, server/fake_client.py, server/fake_player.py, changelog.md, docs/dev-log.md.

server/fake_client.py

@@ -97,6 +97,7 @@ def get_optional_appearance(packet: dict[str, Any]) -> dict[str, Any] | None:
         "bodyTintColor": value.get("bodyTintColor", {}),
         "hairColorFormId": value.get("hairColorFormId", ""),
         "facialHairColorFormId": value.get("facialHairColorFormId", ""),
+        "complexionFormId": value.get("complexionFormId", ""),
         "headParts": [],
         "morphs": [],
         "morphRegions": [],

server/fake_player.py

@@ -51,6 +51,7 @@ DEFAULT_APPEARANCE = {
     "bodyTintColor": {"r": 255, "g": 220, "b": 190, "a": 255},
     "hairColorFormId": "",
     "facialHairColorFormId": "",
+    "complexionFormId": "",
     "headParts": [],
     "morphs": [],
     "morphRegions": [],