feat: create tm-core and apps/cli (#1093)

- add typescript
- add npm workspaces

packages/tm-core/src/config/services/config-merger.service.ts

@@ -0,0 +1,118 @@
+/**
+ * @fileoverview Configuration Merger Service
+ * Responsible for merging configurations from multiple sources with precedence
+ */
+
+import type { PartialConfiguration } from '../../interfaces/configuration.interface.js';
+
+/**
+ * Configuration source with precedence
+ */
+export interface ConfigSource {
+	/** Source name for debugging */
+	name: string;
+	/** Configuration data from this source */
+	config: PartialConfiguration;
+	/** Precedence level (higher = more important) */
+	precedence: number;
+}
+
+/**
+ * Configuration precedence levels (higher number = higher priority)
+ */
+export const CONFIG_PRECEDENCE = {
+	DEFAULTS: 0,
+	GLOBAL: 1, // Reserved for future implementation
+	LOCAL: 2,
+	ENVIRONMENT: 3
+} as const;
+
+/**
+ * ConfigMerger handles merging configurations with precedence rules
+ * Single responsibility: Configuration merging logic
+ */
+export class ConfigMerger {
+	private configSources: ConfigSource[] = [];
+
+	/**
+	 * Add a configuration source
+	 */
+	addSource(source: ConfigSource): void {
+		this.configSources.push(source);
+	}
+
+	/**
+	 * Clear all configuration sources
+	 */
+	clearSources(): void {
+		this.configSources = [];
+	}
+
+	/**
+	 * Merge all configuration sources based on precedence
+	 */
+	merge(): PartialConfiguration {
+		// Sort sources by precedence (lowest first)
+		const sortedSources = [...this.configSources].sort(
+			(a, b) => a.precedence - b.precedence
+		);
+
+		// Merge from lowest to highest precedence
+		let merged: PartialConfiguration = {};
+		for (const source of sortedSources) {
+			merged = this.deepMerge(merged, source.config);
+		}
+
+		return merged;
+	}
+
+	/**
+	 * Deep merge two configuration objects
+	 * Higher precedence values override lower ones
+	 */
+	private deepMerge(target: any, source: any): any {
+		if (!source) return target;
+		if (!target) return source;
+
+		const result = { ...target };
+
+		for (const key in source) {
+			if (source[key] === null || source[key] === undefined) {
+				continue;
+			}
+
+			if (typeof source[key] === 'object' && !Array.isArray(source[key])) {
+				result[key] = this.deepMerge(result[key] || {}, source[key]);
+			} else {
+				result[key] = source[key];
+			}
+		}
+
+		return result;
+	}
+
+	/**
+	 * Get configuration sources for debugging
+	 */
+	getSources(): ConfigSource[] {
+		return [...this.configSources].sort((a, b) => b.precedence - a.precedence);
+	}
+
+	/**
+	 * Check if a source exists
+	 */
+	hasSource(name: string): boolean {
+		return this.configSources.some((source) => source.name === name);
+	}
+
+	/**
+	 * Remove a source by name
+	 */
+	removeSource(name: string): boolean {
+		const initialLength = this.configSources.length;
+		this.configSources = this.configSources.filter(
+			(source) => source.name !== name
+		);
+		return this.configSources.length < initialLength;
+	}
+}