[CI-SKIP] Add technical diagrams

Author: TuxCoding

CONTRIBUTING.md

@@ -0,0 +1,71 @@
+# Contributing Guide
+
+## Architectural overview
+
+```mermaid
+graph TB
+    subgraph "Minecraft Server Platforms"
+        SPIGOT["Spigot/Paper<br/>(Bukkit Module)"]
+        BUNGEE["BungeeCord<br/>(Proxy Module)"]
+        VELOCITY["Velocity<br/>(Velocity Module)"]
+    end
+
+    subgraph "FastLogin Core"
+        CORE["FastLoginCore<br/>Main Logic Engine"]
+        SESSION["LoginSession<br/>Session Management"]
+        AUTH["AuthPlugin Hook<br/>Auth Integration"]
+        RESOLVER["ProxyAgnosticMojangResolver<br/>Profile Resolution"]
+        STORAGE["SQLStorage<br/>Database Layer"]
+        ANTIBOT["AntiBotService<br/>Rate Limiting"]
+    end
+
+    subgraph "Bedrock Support"
+        FLOODGATE["FloodgateManagement<br/>Bedrock Players"]
+        GEYSER["GeyserService<br/>Geyser Integration"]
+        BEDROCK["BedrockService<br/>Base Service"]
+    end
+
+    subgraph "External Services"
+        MOJANG["Mojang API<br/>api.mojang.com"]
+        SESSION_SERVER["Session Server<br/>sessionserver.mojang.com"]
+        DATABASE[(SQL Database<br/>MySQL/SQLite)]
+    end
+
+    subgraph "Async Processing"
+        SCHEDULER["AbstractAsyncScheduler<br/>Thread Pool Management"]
+    end
+
+    subgraph "Messaging"
+        MESSAGES["ChannelMessage<br/>Proxy Messages <br/>(i.e. BungeeCord)"]
+        NAMEKEY["NamespaceKey<br/>Message Routing"]
+    end
+
+    SPIGOT -->|loads| CORE
+    BUNGEE -->|loads| CORE
+    VELOCITY -->|loads| CORE
+
+    CORE -->|manages| SESSION
+    CORE -->|uses| AUTH
+    CORE -->|resolves profiles| RESOLVER
+    CORE -->|persists data| STORAGE
+    CORE -->|checks rate limits| ANTIBOT
+    CORE -->|handles bedrock| FLOODGATE
+
+    FLOODGATE -->|extends| BEDROCK
+    GEYSER -->|extends| BEDROCK
+
+    RESOLVER -->|queries| MOJANG
+    RESOLVER -->|verifies| SESSION_SERVER
+
+    STORAGE -->|connects to| DATABASE
+
+    CORE -->|schedules async| SCHEDULER
+
+    MESSAGES -->|uses| NAMEKEY
+    CORE -->|sends via| MESSAGES
+
+    AUTH -.->|delegates to| SPIGOT
+    AUTH -.->|delegates to| BUNGEE
+
+    ANTIBOT -->|rate limits| RESOLVER
+```

README.md

@@ -32,14 +32,42 @@ Development builds contain the latest changes from the Source-Code. They are ble
 but also include features, enhancements and bug fixes that are not yet in a released version. If you click on the left
 side on `Changes`, you can see iterative change sets leading to a specific build.
 
-~~You can download them from here: [CodeMC(Jenkins)](https://ci.codemc.org/job/Games647/job/FastLogin/)~~
-
-Currently broken due changed usernames. Download it from [here](https://github.com/TuxCoding/FastLogin/releases)
-
-
+You can download them from here: [CodeMC(Jenkins)](https://ci.codemc.org/job/Games647/job/FastLogin/)
 
 ***
 
+## Technical Authentication
+
+```mermaid
+sequenceDiagram
+    autonumber
+    participant C as Client
+    participant S as Server
+    participant M as Mojang
+
+    C->>S: LOGIN_START (name)
+    Note over S: DB: check if username is saved as premium
+    S->>C: ENCRYPTION_REQUEST
+    Note right of C: Offline clients terminates connection here
+    Note right of C: In Offlinemode: LOGIN_SUCCESS is sent directly
+
+    rect rgb(240, 240, 240)
+        C->>M: POST /session/minecraft/join
+        C->>S: ENCRYPTION_RESPONSE
+        Note right of C: Client starts encrypting
+    end
+
+    Note over S: Decrypt and verify token
+    S->>M: GET /hasJoined (async)
+    M->>S: {uuid, name, skin}
+
+    Note over S: Server encrypts traffic
+    Note over S: Inject skin and premium UUID
+    S->>S: Re-inject LOGIN_START(name)
+
+    S->>C: LOGIN_SUCCESS
+```
+
 ## Commands
 
     /premium [player] Label the invoker or the argument as paid account

bungee/src/main/java/com/github/games647/fastlogin/bungee/listener/ConnectListener.java

@@ -235,7 +235,7 @@ public void onServerConnected(ServerConnectedEvent serverConnectedEvent) {
 
         // delay sending force command, because Paper will process the login event asynchronously
         // In this case it means that the force command (plugin message) is already received and processed while
-        // player is still in the login phase and reported to be offline.
+        // player is still in the login phase and reported to be offline
         Runnable loginTask = new ForceLoginTask(plugin.getCore(), player, server, session);
         plugin.getScheduler().runAsync(loginTask);
     }