feat: add TypeScript installation wizard with @clack/prompts TUI

Replace bash mosaic-init with a modern 9-stage wizard:
- SOUL.md identity, USER.md profile, TOOLS.md configuration
- Runtime detection (Claude, Codex, OpenCode) + MCP setup
- Skills catalog with categorized selection
- Quick Start and Advanced modes
- HeadlessPrompter for --non-interactive and CI usage
- ConfigService abstraction layer for future DB migration
- Bundled as single dist/mosaic-wizard.mjs via tsdown
- mosaic init now prefers wizard when Node.js is available
- 30 tests covering stages, templates, and integration

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/config/config-service.ts

@@ -0,0 +1,26 @@
+import type { SoulConfig, UserConfig, ToolsConfig, InstallAction } from '../types.js';
+import { FileConfigAdapter } from './file-adapter.js';
+
+/**
+ * ConfigService interface — abstracts config read/write operations.
+ * Currently backed by FileConfigAdapter (writes .md files from templates).
+ * Designed for future swap to SqliteConfigAdapter or PostgresConfigAdapter.
+ */
+export interface ConfigService {
+  readSoul(): Promise<SoulConfig>;
+  readUser(): Promise<UserConfig>;
+  readTools(): Promise<ToolsConfig>;
+
+  writeSoul(config: SoulConfig): Promise<void>;
+  writeUser(config: UserConfig): Promise<void>;
+  writeTools(config: ToolsConfig): Promise<void>;
+
+  syncFramework(action: InstallAction): Promise<void>;
+}
+
+export function createConfigService(
+  mosaicHome: string,
+  sourceDir: string,
+): ConfigService {
+  return new FileConfigAdapter(mosaicHome, sourceDir);
+}