refactor(background-agent): optimize task timing and constants management

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/delegate-task/timing.ts

@@ -1,4 +1,4 @@
-let POLL_INTERVAL_MS = 500
+let POLL_INTERVAL_MS = 1000
 let MIN_STABILITY_TIME_MS = 10000
 let STABILITY_POLLS_REQUIRED = 3
 let WAIT_FOR_SESSION_INTERVAL_MS = 100
@@ -19,7 +19,7 @@ export function getTimingConfig() {
 }
 
 export function __resetTimingConfig(): void {
-  POLL_INTERVAL_MS = 500
+  POLL_INTERVAL_MS = 1000
   MIN_STABILITY_TIME_MS = 10000
   STABILITY_POLLS_REQUIRED = 3
   WAIT_FOR_SESSION_INTERVAL_MS = 100