Refactor SettingsDefaultsManager: Move to shared directory and update imports

- Moved SettingsDefaultsManager from worker/settings to shared directory.
- Updated all import paths across the codebase to reflect the new location.
- Removed early-settings.ts as its functionality is now handled by SettingsDefaultsManager.
- Adjusted logger and paths to utilize SettingsDefaultsManager for configuration values.

src/shared/SettingsDefaultsManager.ts

@@ -0,0 +1,121 @@
+/**
+ * SettingsDefaultsManager
+ *
+ * Single source of truth for all default configuration values.
+ * Provides methods to get defaults with optional environment variable overrides.
+ */
+
+import { readFileSync, existsSync } from 'fs';
+import { join } from 'path';
+import { homedir } from 'os';
+import { DEFAULT_OBSERVATION_TYPES_STRING, DEFAULT_OBSERVATION_CONCEPTS_STRING } from '../constants/observation-metadata.js';
+
+export interface SettingsDefaults {
+  CLAUDE_MEM_MODEL: string;
+  CLAUDE_MEM_CONTEXT_OBSERVATIONS: string;
+  CLAUDE_MEM_WORKER_PORT: string;
+  // System Configuration
+  CLAUDE_MEM_DATA_DIR: string;
+  CLAUDE_MEM_LOG_LEVEL: string;
+  CLAUDE_MEM_PYTHON_VERSION: string;
+  CLAUDE_CODE_PATH: string;
+  // Token Economics
+  CLAUDE_MEM_CONTEXT_SHOW_READ_TOKENS: string;
+  CLAUDE_MEM_CONTEXT_SHOW_WORK_TOKENS: string;
+  CLAUDE_MEM_CONTEXT_SHOW_SAVINGS_AMOUNT: string;
+  CLAUDE_MEM_CONTEXT_SHOW_SAVINGS_PERCENT: string;
+  // Observation Filtering
+  CLAUDE_MEM_CONTEXT_OBSERVATION_TYPES: string;
+  CLAUDE_MEM_CONTEXT_OBSERVATION_CONCEPTS: string;
+  // Display Configuration
+  CLAUDE_MEM_CONTEXT_FULL_COUNT: string;
+  CLAUDE_MEM_CONTEXT_FULL_FIELD: string;
+  CLAUDE_MEM_CONTEXT_SESSION_COUNT: string;
+  // Feature Toggles
+  CLAUDE_MEM_CONTEXT_SHOW_LAST_SUMMARY: string;
+  CLAUDE_MEM_CONTEXT_SHOW_LAST_MESSAGE: string;
+}
+
+export class SettingsDefaultsManager {
+  /**
+   * Default values for all settings
+   */
+  private static readonly DEFAULTS: SettingsDefaults = {
+    CLAUDE_MEM_MODEL: 'claude-haiku-4-5',
+    CLAUDE_MEM_CONTEXT_OBSERVATIONS: '50',
+    CLAUDE_MEM_WORKER_PORT: '37777',
+    // System Configuration
+    CLAUDE_MEM_DATA_DIR: join(homedir(), '.claude-mem'),
+    CLAUDE_MEM_LOG_LEVEL: 'INFO',
+    CLAUDE_MEM_PYTHON_VERSION: '3.13',
+    CLAUDE_CODE_PATH: '', // Empty means auto-detect via 'which claude'
+    // Token Economics
+    CLAUDE_MEM_CONTEXT_SHOW_READ_TOKENS: 'true',
+    CLAUDE_MEM_CONTEXT_SHOW_WORK_TOKENS: 'true',
+    CLAUDE_MEM_CONTEXT_SHOW_SAVINGS_AMOUNT: 'true',
+    CLAUDE_MEM_CONTEXT_SHOW_SAVINGS_PERCENT: 'true',
+    // Observation Filtering
+    CLAUDE_MEM_CONTEXT_OBSERVATION_TYPES: DEFAULT_OBSERVATION_TYPES_STRING,
+    CLAUDE_MEM_CONTEXT_OBSERVATION_CONCEPTS: DEFAULT_OBSERVATION_CONCEPTS_STRING,
+    // Display Configuration
+    CLAUDE_MEM_CONTEXT_FULL_COUNT: '5',
+    CLAUDE_MEM_CONTEXT_FULL_FIELD: 'narrative',
+    CLAUDE_MEM_CONTEXT_SESSION_COUNT: '10',
+    // Feature Toggles
+    CLAUDE_MEM_CONTEXT_SHOW_LAST_SUMMARY: 'true',
+    CLAUDE_MEM_CONTEXT_SHOW_LAST_MESSAGE: 'false',
+  };
+
+  /**
+   * Get all defaults as an object
+   */
+  static getAllDefaults(): SettingsDefaults {
+    return { ...this.DEFAULTS };
+  }
+
+  /**
+   * Get a default value from defaults (no environment variable override)
+   */
+  static get(key: keyof SettingsDefaults): string {
+    return this.DEFAULTS[key];
+  }
+
+  /**
+   * Get an integer default value
+   */
+  static getInt(key: keyof SettingsDefaults): number {
+    const value = this.get(key);
+    return parseInt(value, 10);
+  }
+
+  /**
+   * Get a boolean default value
+   */
+  static getBool(key: keyof SettingsDefaults): boolean {
+    const value = this.get(key);
+    return value === 'true';
+  }
+
+  /**
+   * Load settings from file with fallback to defaults
+   * Returns merged settings with defaults as fallback
+   */
+  static loadFromFile(settingsPath: string): SettingsDefaults {
+    if (!existsSync(settingsPath)) {
+      return this.getAllDefaults();
+    }
+
+    const settingsData = readFileSync(settingsPath, 'utf-8');
+    const settings = JSON.parse(settingsData);
+
+    // Merge file settings with defaults (flat schema, no env wrapper)
+    const result: SettingsDefaults = { ...this.DEFAULTS };
+    for (const key of Object.keys(this.DEFAULTS) as Array<keyof SettingsDefaults>) {
+      if (settings[key] !== undefined) {
+        result[key] = settings[key];
+      }
+    }
+
+    return result;
+  }
+}