fix: use cwd instead of CLAUDE_CONFIG_DIR for observer session isolation (#845)

The previous approach (PR #837) set CLAUDE_CONFIG_DIR to isolate observer
sessions from `claude --resume`. However, this broke authentication because
Claude Code stores credentials in the config directory.

This fix uses the SDK's `cwd` option instead:
- Observer sessions run with cwd=~/.claude-mem/observer-sessions/
- Project name = path.basename(cwd) = "observer-sessions"
- Sessions won't appear when running `claude --resume` from actual projects
- Authentication works because ~/.claude/ config is preserved

Changes:
- ProcessRegistry.ts: Remove CLAUDE_CONFIG_DIR override from spawn
- SDKAgent.ts: Add cwd option to query() pointing to observer dir
- paths.ts: Rename OBSERVER_CONFIG_DIR to OBSERVER_SESSIONS_DIR

Fixes regression from #837

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src/services/worker/ProcessRegistry.ts

@@ -19,7 +19,6 @@
 import { spawn, exec, ChildProcess } from 'child_process';
 import { promisify } from 'util';
 import { logger } from '../../utils/logger.js';
-import { OBSERVER_CONFIG_DIR, ensureDir } from '../../shared/paths.js';
 
 const execAsync = promisify(exec);
 
@@ -189,14 +188,10 @@ export async function reapOrphanedProcesses(activeSessionIds: Set<number>): Prom
  * The SDK's spawnClaudeCodeProcess option allows us to intercept subprocess
  * creation and capture the PID before the SDK hides it.
  *
- * IMPORTANT (Issue #832): We set CLAUDE_CONFIG_DIR to isolate observer sessions.
- * This prevents observer sessions from appearing in `claude --resume` list,
- * which was causing 34%+ of resume entries to be internal plugin sessions.
+ * NOTE: Session isolation is handled via the `cwd` option in SDKAgent.ts,
+ * NOT via CLAUDE_CONFIG_DIR (which breaks authentication).
  */
 export function createPidCapturingSpawn(sessionDbId: number) {
-  // Ensure observer config directory exists
-  ensureDir(OBSERVER_CONFIG_DIR);
-
   return (spawnOptions: {
     command: string;
     args: string[];
@@ -204,15 +199,9 @@ export function createPidCapturingSpawn(sessionDbId: number) {
     env?: NodeJS.ProcessEnv;
     signal?: AbortSignal;
   }) => {
-    // Inject CLAUDE_CONFIG_DIR to isolate observer sessions (Issue #832)
-    const isolatedEnv = {
-      ...spawnOptions.env,
-      CLAUDE_CONFIG_DIR: OBSERVER_CONFIG_DIR
-    };
-
     const child = spawn(spawnOptions.command, spawnOptions.args, {
       cwd: spawnOptions.cwd,
-      env: isolatedEnv,
+      env: spawnOptions.env,
       stdio: ['pipe', 'pipe', 'pipe'],
       signal: spawnOptions.signal, // CRITICAL: Pass signal for AbortController integration
       windowsHide: true

src/services/worker/SDKAgent.ts

@@ -16,7 +16,7 @@ import { SessionManager } from './SessionManager.js';
 import { logger } from '../../utils/logger.js';
 import { buildInitPrompt, buildObservationPrompt, buildSummaryPrompt, buildContinuationPrompt } from '../../sdk/prompts.js';
 import { SettingsDefaultsManager } from '../../shared/SettingsDefaultsManager.js';
-import { USER_SETTINGS_PATH } from '../../shared/paths.js';
+import { USER_SETTINGS_PATH, OBSERVER_SESSIONS_DIR, ensureDir } from '../../shared/paths.js';
 import type { ActiveSession, SDKUserMessage } from '../worker-types.js';
 import { ModeManager } from '../domain/ModeManager.js';
 import { processAgentResponse, type WorkerRef } from './agents/index.js';
@@ -101,10 +101,15 @@ export class SDKAgent {
     // Run Agent SDK query loop
     // Only resume if we have a captured memory session ID
     // Use custom spawn to capture PIDs for zombie process cleanup (Issue #737)
+    // Use dedicated cwd to isolate observer sessions from user's `claude --resume` list
+    ensureDir(OBSERVER_SESSIONS_DIR);
     const queryResult = query({
       prompt: messageGenerator,
       options: {
         model: modelId,
+        // Isolate observer sessions - they'll appear under project "observer-sessions"
+        // instead of polluting user's actual project resume lists
+        cwd: OBSERVER_SESSIONS_DIR,
         // Only resume if BOTH: (1) we have a memorySessionId AND (2) this isn't the first prompt
         // On worker restart, memorySessionId may exist from a previous SDK session but we
         // need to start fresh since the SDK context was lost

src/shared/paths.ts

@@ -38,9 +38,9 @@ export const USER_SETTINGS_PATH = join(DATA_DIR, 'settings.json');
 export const DB_PATH = join(DATA_DIR, 'claude-mem.db');
 export const VECTOR_DB_DIR = join(DATA_DIR, 'vector-db');
 
-// Isolated config directory for observer sessions (Issue #832)
-// This prevents observer sessions from appearing in `claude --resume` list
-export const OBSERVER_CONFIG_DIR = join(DATA_DIR, 'observer-config');
+// Observer sessions directory - used as cwd for SDK queries
+// Sessions here won't appear in user's `claude --resume` for their actual projects
+export const OBSERVER_SESSIONS_DIR = join(DATA_DIR, 'observer-sessions');
 
 // Claude integration paths
 export const CLAUDE_SETTINGS_PATH = join(CLAUDE_CONFIG_DIR, 'settings.json');