refactor: consolidate MCP factory, add non-TTY support, auto-detect transcript watchers

- Phase 1: Replace 5 duplicate MCP installers with config-driven factory, extract
  shared context-injection and json-utils utilities, fix process.execPath usage
- Phase 2: Add non-TTY fallback for @clack/prompts to prevent ENOENT in CI/Docker
- Phase 3: Wire GeminiCliHooksInstaller through hook command framework with adapter
- Phase 4: Auto-start transcript watchers on worker boot when config exists

Net -107 lines via DRY consolidation of duplicated installer logic.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/utils/context-injection.ts

@@ -0,0 +1,68 @@
+/**
+ * Shared context injection utilities for claude-mem.
+ *
+ * Provides tag constants and a function to inject or update a
+ * <claude-mem-context> section in any markdown file. Used by
+ * MCP integrations and OpenCode installer.
+ */
+
+import path from 'path';
+import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'fs';
+
+// ============================================================================
+// Tag Constants
+// ============================================================================
+
+export const CONTEXT_TAG_OPEN = '<claude-mem-context>';
+export const CONTEXT_TAG_CLOSE = '</claude-mem-context>';
+
+// ============================================================================
+// Context Injection
+// ============================================================================
+
+/**
+ * Inject or update a <claude-mem-context> section in a markdown file.
+ * Creates the file if it doesn't exist. Preserves content outside the tags.
+ *
+ * @param filePath - Absolute path to the target markdown file.
+ * @param contextContent - The content to place between the context tags.
+ * @param headerLine - Optional first line written when creating a new file
+ *                     (e.g. `"# Claude-Mem Memory Context"` for AGENTS.md).
+ */
+export function injectContextIntoMarkdownFile(
+  filePath: string,
+  contextContent: string,
+  headerLine?: string,
+): void {
+  const parentDirectory = path.dirname(filePath);
+  mkdirSync(parentDirectory, { recursive: true });
+
+  const wrappedContent = `${CONTEXT_TAG_OPEN}\n${contextContent}\n${CONTEXT_TAG_CLOSE}`;
+
+  if (existsSync(filePath)) {
+    let existingContent = readFileSync(filePath, 'utf-8');
+
+    const tagStartIndex = existingContent.indexOf(CONTEXT_TAG_OPEN);
+    const tagEndIndex = existingContent.indexOf(CONTEXT_TAG_CLOSE);
+
+    if (tagStartIndex !== -1 && tagEndIndex !== -1) {
+      // Replace existing section
+      existingContent =
+        existingContent.slice(0, tagStartIndex) +
+        wrappedContent +
+        existingContent.slice(tagEndIndex + CONTEXT_TAG_CLOSE.length);
+    } else {
+      // Append section
+      existingContent = existingContent.trimEnd() + '\n\n' + wrappedContent + '\n';
+    }
+
+    writeFileSync(filePath, existingContent, 'utf-8');
+  } else {
+    // Create new file
+    if (headerLine) {
+      writeFileSync(filePath, `${headerLine}\n\n${wrappedContent}\n`, 'utf-8');
+    } else {
+      writeFileSync(filePath, wrappedContent + '\n', 'utf-8');
+    }
+  }
+}

src/utils/json-utils.ts

@@ -0,0 +1,26 @@
+/**
+ * Shared JSON file utilities for claude-mem.
+ *
+ * Provides safe read/write helpers used across the CLI and services.
+ */
+
+import { existsSync, readFileSync } from 'fs';
+import { logger } from './logger.js';
+
+/**
+ * Read a JSON file safely, returning a default value if the file
+ * does not exist or contains corrupt JSON.
+ *
+ * @param filePath - Absolute path to the JSON file.
+ * @param defaultValue - Value returned when the file is missing or unreadable.
+ * @returns The parsed JSON content, or `defaultValue` on failure.
+ */
+export function readJsonSafe<T>(filePath: string, defaultValue: T): T {
+  if (!existsSync(filePath)) return defaultValue;
+  try {
+    return JSON.parse(readFileSync(filePath, 'utf-8'));
+  } catch (error) {
+    logger.error('JSON', `Corrupt JSON file, using default`, { path: filePath }, error as Error);
+    return defaultValue;
+  }
+}