Create a docs folder, add auth & architecture docs (#2623)

## Description:
Create docs folder
## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

docs/API.md

@@ -0,0 +1,208 @@
+# API Usage
+
+## Games
+
+### List Game Metadata
+
+Get game IDs and basic metadata for games that started within a specified time range. Results are sorted by start time and paginated.
+
+**Constraints:**
+
+- Maximum time range: 2 days
+- Maximum limit per request: 1000 games
+
+**Endpoint:**
+
+```
+GET https://api.openfront.io/public/games
+```
+
+**Query Parameters:**
+
+- `start` (required): ISO 8601 timestamp
+- `end` (required): ISO 8601 timestamp
+- `type` (optional): Game type, must be one of `[Private, Public, Singleplayer]`
+- `limit` (optional): Number of results (max 1000, default 50)
+- `offset` (optional): Pagination offset
+
+**Example Request:**
+
+```bash
+curl "https://api.openfront.io/public/games?start=2025-10-25T00:00:00Z&end=2025-10-26T23:59:59Z&type=Singleplayer&limit=10&offset=5"
+```
+
+**Response:**
+
+```json
+[
+  {
+    "game": "ABSgwin6",
+    "start": "2025-10-25T00:00:10.526Z",
+    "end": "2025-10-25T00:19:45.187Z",
+    "type": "Singleplayer",
+    "mode": "Free For All",
+    "difficulty": "Medium"
+  }
+]
+```
+
+The response includes a `Content-Range` header indicating pagination (e.g., `games 5-15/399`).
+
+---
+
+### Get Game Info
+
+Retrieve detailed information about a specific game.
+
+**Endpoint:**
+
+```
+GET https://api.openfront.io/public/game/:gameId
+```
+
+**Query Parameters:**
+
+- `turns` (optional): Set to `false` to exclude turn data and reduce response size
+
+**Examples:**
+
+```bash
+# Full game data
+curl "https://api.openfront.io/public/game/ABSgwin6"
+
+# Without turn data
+curl "https://api.openfront.io/public/game/ABSgwin6?turns=false"
+```
+
+**Note:** Public player IDs are stripped from game records for privacy.
+
+## Players
+
+### Get Player Info
+
+Retrieve information and stats for a specific player.
+
+**Endpoint:**
+
+```
+GET https://api.openfront.io/public/player/:playerId
+```
+
+**Example:**
+
+```bash
+curl "https://api.openfront.io/public/player/HabCsQYR"
+```
+
+### Get Player Sessions
+
+Retrieve a list of games & client ids (session ids) for a specific player.
+
+**Endpoint:**
+
+```
+GET https://api.openfront.io/public/player/:playerId/sessions
+```
+
+**Example:**
+
+```bash
+curl "https://api.openfront.io/public/player/HabCsQYR/sessions"
+```
+
+## Clans
+
+### Clan Leaderboard
+
+Shows the top 100 clans by `weighted wins`.
+
+**Endpoint:**
+
+```
+GET https://api.openfront.io/public/clans/leaderboard
+```
+
+Weighted wins have a half-life of 30 days to favor recent wins.
+
+Weighted wins are calculated using the following formula:
+
+```
+FUNCTION calculateScore(session: ClanSession, decay: NUMBER = 1) → NUMBER
+    // 1. Calculate average team size
+    avgTeamSize ← session.totalPlayerCount ÷ session.numTeams
+
+    // 2. Determine how much the clan contributed to their team
+    //    (clan players divided by average players per team)
+    clanMemberRatio ← session.clanPlayerCount ÷ avgTeamSize
+
+    // 3. Apply decay factor (e.g., for older sessions)
+    weightedValue ← clanMemberRatio × decay
+
+    // 4. Calculate match difficulty based on number of teams
+    //    More teams → harder to win → higher reward for victory
+    //    Uses square root to avoid extreme scaling
+    difficulty ← MAX(1, √(session.numTeams - 1))
+
+    // 5. Return final score:
+    //    - Win:  reward is multiplied by difficulty
+    //    - Loss: penalty is divided by difficulty (less punishment in harder matches)
+    IF session.hasWon THEN
+        RETURN weightedValue × difficulty
+    ELSE
+        RETURN weightedValue ÷ difficulty
+    END IF
+END FUNCTION
+```
+
+### Clan stats
+
+Displays comprehensive clan performance statistics for a specified clan over a chosen time range. If no time range is provided, it shows lifetime stats (starting from early November 2025).
+
+Key metrics include:
+
+- Total games, wins, losses, and win rate
+- Win/loss ratio and weighted win/loss ratio\* broken down by:
+  - Team type (e.g., 2 teams, 3 teams, duos, trios, etc)
+  - Number of teams in the game (2 teams, 5 teams, 20 teams, etc)
+
+**Note:** No decay is used, so weighted wins will be different from in the leaderboard.
+
+**Endpoint**
+
+```
+GET https://openfront.io/public/clan/:clanTag
+```
+
+**Query Parameters:**
+
+- `start` (optional): ISO 8601 timestamp
+- `end` (optional): ISO 8601 timestamp
+
+**Example**
+
+```bash
+curl https://api.openfront.io/public/clan/UN?start=2025-11-15T00:00:00Z &
+end=2025-11-18T23:59:59Z
+```
+
+### Clan Sessions
+
+A clan session is created any time a player with that clan tag is in a public team game. If no start or end query parameter is provided, lifetime sessions (starting early November 2025) are shown.
+
+**Endpoint**
+
+```
+GET https://api.openfront.io/public/clan/:clanTag/sessions
+```
+
+**Query Parameters:**
+
+- `start` (optional): ISO 8601 timestamp
+- `end` (optional): ISO 8601 timestamp
+
+**Example**
+
+```bash
+curl https://api.openfront.io/public/clan/UN/sessions?start=2025-11-15T00:00:00Z &
+end=2025-11-18T23:59:59Z
+```