Fix XSS, add per-step timeout/retry to workflow engine

index.html:
- Escape started_by in execution list, execution cards, and execution detail modal
- Escape schedule name in schedules list

server.js:
- Per-step timeout: step.timeout (seconds) overrides global COMMAND_TIMEOUT_MS (5s-600s range)
- Per-step retry: step.retries (max 5) with step.retryDelayMs (max 30s) re-sends command on failure
  with command_retry log entries showing attempt/max_retries progress

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

server.js

@@ -987,7 +987,7 @@ async function executeCommandStep(executionId, step, stepNumber, params = {}) {
       }
 
       // Send command to worker
-      const commandId = crypto.randomUUID();
+      let commandId = crypto.randomUUID();
 
       await addExecutionLog(executionId, {
         step: stepNumber,
@@ -998,21 +998,56 @@ async function executeCommandStep(executionId, step, stepNumber, params = {}) {
         timestamp: new Date().toISOString()
       });
 
+      // Per-step timeout override: step.timeout (seconds) overrides global default
+      const stepTimeoutMs = step.timeout
+        ? Math.min(Math.max(parseInt(step.timeout, 10) * 1000, 5000), 600000)
+        : COMMAND_TIMEOUT_MS;
+
       workerWs.send(JSON.stringify({
         type: 'execute_command',
         execution_id: executionId,
         command_id: commandId,
         command: command,
         worker_id: workerId,
-        timeout: COMMAND_TIMEOUT_MS
+        timeout: stepTimeoutMs
       }));
 
-      // Wait for command result (with timeout)
-      const result = await waitForCommandResult(executionId, commandId, COMMAND_TIMEOUT_MS);
+      // Per-step retry: step.retries (default 0) with step.retryDelayMs (default 2000)
+      const maxRetries = Math.min(parseInt(step.retries || 0, 10), 5);
+      const retryDelayMs = Math.min(parseInt(step.retryDelayMs || 2000, 10), 30000);
+
+      let result;
+      let attempt = 0;
+      while (true) {
+        result = await waitForCommandResult(executionId, commandId, stepTimeoutMs);
+        if (result.success || attempt >= maxRetries) break;
+        attempt++;
+        await addExecutionLog(executionId, {
+          step: stepNumber,
+          action: 'command_retry',
+          worker_id: workerId,
+          attempt,
+          max_retries: maxRetries,
+          message: `Command failed, retrying (attempt ${attempt}/${maxRetries})...`,
+          timestamp: new Date().toISOString()
+        });
+        await new Promise(r => setTimeout(r, retryDelayMs));
+        // Re-send command for retry
+        const retryCommandId = crypto.randomUUID();
+        await addExecutionLog(executionId, {
+          step: stepNumber, action: 'command_sent', worker_id: workerId,
+          command: command, command_id: retryCommandId, timestamp: new Date().toISOString()
+        });
+        workerWs.send(JSON.stringify({
+          type: 'execute_command', execution_id: executionId, command_id: retryCommandId,
+          command: command, worker_id: workerId, timeout: stepTimeoutMs
+        }));
+        commandId = retryCommandId; // update for next waitForCommandResult call
+      }
       results.push(result);
 
       if (!result.success) {
-        // Command failed, workflow should stop
+        // Command failed after all retries, workflow should stop
         return false;
       }
     }