refactor: split types.ts into domain-specific files

- src/types/common.ts - ApprovalMode, NyxMood, ModelRouting, ProviderCallEntry
- src/types/providers.ts - Provider, ProviderConfig, Message, PROVIDERS
- src/types/tools.ts - ToolCall, ToolResult, FileDiff
- src/types/sessions.ts - Checkpoint, Persona, Theme, SessionState, personas, system prompt
- src/types/commands.ts - SlashCommand, SLASH_COMMANDS (60+ commands)
- src/types/index.ts - Re-exports for backward compatibility
- Updated all 16 import statements across codebase
- Fixed SessionState provider type from string to Provider
- Fixed apiKeys type from Record<string,string> to Record<Provider,string>

types.ts went from 834 lines to 0 (replaced by 5 focused files)

Author: thegreatalxx

dist/providers/client.d.ts

@@ -1,4 +1,4 @@
-import { Provider, Message, ToolCall, ModelRouting } from '../core/types.js';
+import { Provider, Message, ToolCall, ModelRouting } from '../types/index.js';
 export declare function retryWithBackoff<T>(fn: () => Promise<T>, context: string, signal?: AbortSignal): Promise<T>;
 export interface StreamChunk {
     type: 'text' | 'tool_call' | 'tool_result' | 'agent_step' | 'done' | 'error';

dist/providers/client.d.ts.map

@@ -1,4 +1,4 @@
-import { SessionState, Checkpoint, Message } from '../core/types.js';
+import { SessionState, Checkpoint, Message } from '../types/index.js';
 export interface HookEntry {
     matcher?: string;
     command: string;