refactor: consolidate config types and remove file-based config

Tickets: #2, #3

- Remove duplicate type definitions from shared/lib/config.ts
- Import types from schema files (game-settings.ts, guild-settings.ts)
- Add GuildConfig interface to guild-settings.ts schema
- Rename ModerationConfig to ModerationCaseConfig in moderation.service.ts
- Delete shared/config/config.json and shared/scripts/migrate-config-to-db.ts
- Update settings API to use gameSettingsService exclusively
- Return DB format (strings) from API instead of runtime BigInts
- Fix moderation service tests to pass config as parameter

Breaking Changes:
- Removes legacy file-based configuration system
- API now returns database format with string values for BigInt fields

shared/modules/moderation/moderation.service.ts

@@ -5,7 +5,7 @@ import type { CreateCaseOptions, ClearCaseOptions, SearchCasesFilter } from "@/m
 import { getUserWarningEmbed } from "@/modules/moderation/moderation.view";
 import { CaseType } from "@shared/lib/constants";
 
-export interface ModerationConfig {
+export interface ModerationCaseConfig {
     dmOnWarn?: boolean;
     autoTimeoutThreshold?: number;
 }
@@ -66,7 +66,7 @@ export class ModerationService {
         guildName?: string;
         dmTarget?: { send: (options: any) => Promise<any> };
         timeoutTarget?: { timeout: (duration: number, reason: string) => Promise<any> };
-        config?: ModerationConfig;
+        config?: ModerationCaseConfig;
     }) {
         const moderationCase = await this.createCase({
             type: CaseType.WARN,