feat(agent): require absolute path for command in hermes/cursor agent configs

BREAKING: HermesAgentConfig.command and CursorAgentConfig.command are now
required string fields (absolute path to CLI binary). Validation rejects
non-absolute paths at construction time.

- Eliminates PATH resolution ambiguity in spawned worker processes
- spawnCli: explicit env: process.env for clarity
- bundle-entry: WORKFLOW_CURSOR_COMMAND is now required
- Updated tests for both agents

packages/workflow-template-develop/bundle-entry.ts

@@ -31,7 +31,7 @@ const llmProvider = {
 };
 
 const agent = createCursorAgent({
-  command: optionalEnv("WORKFLOW_CURSOR_COMMAND"),
+  command: requireEnv("WORKFLOW_CURSOR_COMMAND"),
   model: optionalEnv("WORKFLOW_CURSOR_MODEL"),
   timeout: optionalEnv("WORKFLOW_CURSOR_TIMEOUT")
     ? Number(optionalEnv("WORKFLOW_CURSOR_TIMEOUT"))