feat(01-01): refactor SubagentDetailBuilder to use FileSystemProvider

- Remove dynamic fs/promises, os, and path imports from SubagentDetailBuilder
- Add fsProvider and projectsDir parameters to buildSubagentDetail function
- Replace fs.access() with fsProvider.exists() for file existence check
- Replace os.homedir() path construction with projectsDir parameter
- Update ChunkBuilder.buildSubagentDetail() to accept and pass new parameters
- Update IPC subagents handler to obtain provider and projectsDir from ProjectScanner
- Update initializeSubagentHandlers to accept ProjectScanner parameter
- Update handlers.ts to pass ProjectScanner to subagent handler initialization

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

src/main/ipc/handlers.ts

@@ -72,7 +72,7 @@ export function initializeIpcHandlers(
   initializeProjectHandlers(scanner);
   initializeSessionHandlers(scanner, parser, resolver, builder, cache);
   initializeSearchHandlers(scanner);
-  initializeSubagentHandlers(builder, cache, parser, resolver);
+  initializeSubagentHandlers(builder, cache, parser, resolver, scanner);
   initializeUpdaterHandlers(updater);
   if (sshManager && sshModeSwitchCallback) {
     initializeSshHandlers(sshManager, sshModeSwitchCallback);
@@ -110,7 +110,7 @@ export function reinitializeServiceHandlers(
   initializeProjectHandlers(scanner);
   initializeSessionHandlers(scanner, parser, resolver, builder, cache);
   initializeSearchHandlers(scanner);
-  initializeSubagentHandlers(builder, cache, parser, resolver);
+  initializeSubagentHandlers(builder, cache, parser, resolver, scanner);
   logger.info('Service handlers re-initialized after mode switch');
 }
 

src/main/ipc/subagents.ts

@@ -12,7 +12,13 @@ import { type SubagentDetail } from '../types';
 
 import { validateProjectId, validateSessionId, validateSubagentId } from './guards';
 
-import type { ChunkBuilder, DataCache, SessionParser, SubagentResolver } from '../services';
+import type {
+  ChunkBuilder,
+  DataCache,
+  ProjectScanner,
+  SessionParser,
+  SubagentResolver,
+} from '../services';
 
 const logger = createLogger('IPC:subagents');
 
@@ -21,6 +27,7 @@ let chunkBuilder: ChunkBuilder;
 let dataCache: DataCache;
 let sessionParser: SessionParser;
 let subagentResolver: SubagentResolver;
+let projectScanner: ProjectScanner;
 
 /**
  * Initializes subagent handlers with service instances.
@@ -29,12 +36,14 @@ export function initializeSubagentHandlers(
   builder: ChunkBuilder,
   cache: DataCache,
   parser: SessionParser,
-  resolver: SubagentResolver
+  resolver: SubagentResolver,
+  scanner: ProjectScanner
 ): void {
   chunkBuilder = builder;
   dataCache = cache;
   sessionParser = parser;
   subagentResolver = resolver;
+  projectScanner = scanner;
 }
 
 /**
@@ -97,13 +106,19 @@ async function handleGetSubagentDetail(
       return subagentDetail;
     }
 
+    // Get provider and projectsDir from projectScanner
+    const fsProvider = projectScanner.getFileSystemProvider();
+    const projectsDir = projectScanner.getProjectsDir();
+
     // Build subagent detail
     const builtDetail = await chunkBuilder.buildSubagentDetail(
       safeProjectId,
       safeSessionId,
       safeSubagentId,
       sessionParser,
-      subagentResolver
+      subagentResolver,
+      fsProvider,
+      projectsDir
     );
 
     if (!builtDetail) {

src/main/services/analysis/ChunkBuilder.ts

@@ -55,6 +55,7 @@ import { buildGroups as buildConversationGroups } from './ConversationGroupBuild
 import { buildSubagentDetail as buildSubagentDetailFn } from './SubagentDetailBuilder';
 
 import type { SubagentResolver } from '../discovery/SubagentResolver';
+import type { FileSystemProvider } from '../infrastructure/FileSystemProvider';
 import type { SessionParser } from '../parsing/SessionParser';
 
 export class ChunkBuilder {
@@ -428,7 +429,9 @@ export class ChunkBuilder {
     sessionId: string,
     subagentId: string,
     sessionParser: SessionParser,
-    subagentResolver: SubagentResolver
+    subagentResolver: SubagentResolver,
+    fsProvider: FileSystemProvider,
+    projectsDir: string
   ): Promise<SubagentDetail | null> {
     // Delegate to the extracted module, passing buildChunks as a callback
     return buildSubagentDetailFn(
@@ -437,7 +440,9 @@ export class ChunkBuilder {
       subagentId,
       sessionParser,
       subagentResolver,
-      (messages, subagents) => this.buildChunks(messages, subagents)
+      (messages, subagents) => this.buildChunks(messages, subagents),
+      fsProvider,
+      projectsDir
     );
   }
 }

src/main/services/analysis/SubagentDetailBuilder.ts

@@ -16,12 +16,14 @@ import {
 } from '@main/types';
 import { countTokens } from '@main/utils/tokenizer';
 import { createLogger } from '@shared/utils/logger';
+import * as path from 'path';
 
 const logger = createLogger('Service:SubagentDetailBuilder');
 
 import { buildSemanticStepGroups } from './SemanticStepGrouper';
 
 import type { SubagentResolver } from '../discovery/SubagentResolver';
+import type { FileSystemProvider } from '../infrastructure/FileSystemProvider';
 import type { SessionParser } from '../parsing/SessionParser';
 
 /**
@@ -34,6 +36,8 @@ import type { SessionParser } from '../parsing/SessionParser';
  * @param sessionParser - SessionParser instance for parsing subagent file
  * @param subagentResolver - SubagentResolver instance for nested subagents
  * @param buildChunksFn - Function to build chunks from messages and subagents
+ * @param fsProvider - FileSystemProvider for file existence checks
+ * @param projectsDir - Projects directory path
  * @returns SubagentDetail or null if not found
  */
 export async function buildSubagentDetail(
@@ -42,21 +46,21 @@ export async function buildSubagentDetail(
   subagentId: string,
   sessionParser: SessionParser,
   subagentResolver: SubagentResolver,
-  buildChunksFn: (messages: ParsedMessage[], subagents: Process[]) => EnhancedChunk[]
+  buildChunksFn: (messages: ParsedMessage[], subagents: Process[]) => EnhancedChunk[],
+  fsProvider: FileSystemProvider,
+  projectsDir: string
 ): Promise<SubagentDetail | null> {
   try {
-    const fs = await import('fs/promises');
-    const path = await import('path');
-    const os = await import('os');
-
     // Construct path to subagent JSONL file
-    const claudeDir = path.join(os.homedir(), '.claude', 'projects');
-    const subagentPath = path.join(claudeDir, projectId, 'subagents', `agent-${subagentId}.jsonl`);
+    const subagentPath = path.join(
+      projectsDir,
+      projectId,
+      'subagents',
+      `agent-${subagentId}.jsonl`
+    );
 
     // Check if file exists
-    try {
-      await fs.access(subagentPath);
-    } catch {
+    if (!(await fsProvider.exists(subagentPath))) {
       logger.warn(`Subagent file not found: ${subagentPath}`);
       return null;
     }