fix: resume BLOCKED tasks in preserved sandbox so Claude finds its session

When a task ran in a sandbox (/tmp/claudomator-sandbox-*) and went BLOCKED,
Claude stored its session under the sandbox path as the project slug. The
resume execution was running in project_dir, causing Claude to look for the
session in the wrong project directory and fail with "No conversation found".

Fix: carry SandboxDir through BlockedError → Execution → resume execution,
and run the resume in that directory so the session lookup succeeds.

- BlockedError gains SandboxDir field; claude.go sets it on BLOCKED exit
- storage.Execution gains SandboxDir (persisted via new sandbox_dir column)
- executor.go stores blockedErr.SandboxDir in the execution record
- server.go copies SandboxDir from latest execution to the resume execution
- claude.go uses e.SandboxDir as working dir for resume when set

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

1 files changed, 14 insertions, 10 deletions

diff --git a/internal/storage/db.go b/internal/storage/db.go
index 01ce902..5ba0786 100644
--- a/internal/storage/db.go
+++ b/internal/storage/db.go
@@ -80,6 +80,7 @@ func (s *DB) migrate() error {
 		`ALTER TABLE tasks ADD COLUMN rejection_comment TEXT`,
 		`ALTER TABLE tasks ADD COLUMN question_json TEXT`,
 		`ALTER TABLE executions ADD COLUMN session_id TEXT`,
+		`ALTER TABLE executions ADD COLUMN sandbox_dir TEXT`,
 	}
 	for _, m := range migrations {
 		if _, err := s.db.Exec(m); err != nil {
@@ -348,7 +349,8 @@ type Execution struct {
 	ArtifactDir string
 	CostUSD     float64
 	ErrorMsg    string
-	SessionID   string // claude --session-id; persisted for resume
+	SessionID  string // claude --session-id; persisted for resume
+	SandboxDir string // preserved sandbox path when task is BLOCKED; resume must run here
 
 	// In-memory only: set when creating a resume execution, not stored in DB.
 	ResumeSessionID string
@@ -358,23 +360,23 @@ type Execution struct {
 // CreateExecution inserts an execution record.
 func (s *DB) CreateExecution(e *Execution) error {
 	_, err := s.db.Exec(`
-		INSERT INTO executions (id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id)
-		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		INSERT INTO executions (id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id, sandbox_dir)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
 		e.ID, e.TaskID, e.StartTime.UTC(), e.EndTime.UTC(), e.ExitCode, e.Status,
-		e.StdoutPath, e.StderrPath, e.ArtifactDir, e.CostUSD, e.ErrorMsg, e.SessionID,
+		e.StdoutPath, e.StderrPath, e.ArtifactDir, e.CostUSD, e.ErrorMsg, e.SessionID, e.SandboxDir,
 	)
 	return err
 }
 
 // GetExecution retrieves an execution by ID.
 func (s *DB) GetExecution(id string) (*Execution, error) {
-	row := s.db.QueryRow(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id FROM executions WHERE id = ?`, id)
+	row := s.db.QueryRow(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id, sandbox_dir FROM executions WHERE id = ?`, id)
 	return scanExecution(row)
 }
 
 // ListExecutions returns executions for a task.
 func (s *DB) ListExecutions(taskID string) ([]*Execution, error) {
-	rows, err := s.db.Query(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id FROM executions WHERE task_id = ? ORDER BY start_time DESC`, taskID)
+	rows, err := s.db.Query(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id, sandbox_dir FROM executions WHERE task_id = ? ORDER BY start_time DESC`, taskID)
 	if err != nil {
 		return nil, err
 	}
@@ -393,7 +395,7 @@ func (s *DB) ListExecutions(taskID string) ([]*Execution, error) {
 
 // GetLatestExecution returns the most recent execution for a task.
 func (s *DB) GetLatestExecution(taskID string) (*Execution, error) {
-	row := s.db.QueryRow(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id FROM executions WHERE task_id = ? ORDER BY start_time DESC LIMIT 1`, taskID)
+	row := s.db.QueryRow(`SELECT id, task_id, start_time, end_time, exit_code, status, stdout_path, stderr_path, artifact_dir, cost_usd, error_msg, session_id, sandbox_dir FROM executions WHERE task_id = ? ORDER BY start_time DESC LIMIT 1`, taskID)
 	return scanExecution(row)
 }
 
@@ -518,10 +520,10 @@ func (s *DB) UpdateTaskQuestion(taskID, questionJSON string) error {
 func (s *DB) UpdateExecution(e *Execution) error {
 	_, err := s.db.Exec(`
 		UPDATE executions SET end_time = ?, exit_code = ?, status = ?, cost_usd = ?, error_msg = ?,
-		stdout_path = ?, stderr_path = ?, artifact_dir = ?, session_id = ?
+		stdout_path = ?, stderr_path = ?, artifact_dir = ?, session_id = ?, sandbox_dir = ?
 		WHERE id = ?`,
 		e.EndTime.UTC(), e.ExitCode, e.Status, e.CostUSD, e.ErrorMsg,
-		e.StdoutPath, e.StderrPath, e.ArtifactDir, e.SessionID, e.ID,
+		e.StdoutPath, e.StderrPath, e.ArtifactDir, e.SessionID, e.SandboxDir, e.ID,
 	)
 	return err
 }
@@ -576,12 +578,14 @@ func scanTaskRows(rows *sql.Rows) (*task.Task, error) {
 func scanExecution(row scanner) (*Execution, error) {
 	var e Execution
 	var sessionID sql.NullString
+	var sandboxDir sql.NullString
 	err := row.Scan(&e.ID, &e.TaskID, &e.StartTime, &e.EndTime, &e.ExitCode, &e.Status,
-		&e.StdoutPath, &e.StderrPath, &e.ArtifactDir, &e.CostUSD, &e.ErrorMsg, &sessionID)
+		&e.StdoutPath, &e.StderrPath, &e.ArtifactDir, &e.CostUSD, &e.ErrorMsg, &sessionID, &sandboxDir)
 	if err != nil {
 		return nil, err
 	}
 	e.SessionID = sessionID.String
+	e.SandboxDir = sandboxDir.String
 	return &e, nil
 }