Prevent premature exit in non-interactive mode when tasks pending (#216) (#217)

Detects non-interactive environments (CI, opencode run) and prevents session idle when:
- Background tasks are still running
- Incomplete todos remain in the queue

Changes:
- Add isNonInteractive() detector for CI/headless environment detection
- Export detector from non-interactive-env hook module
- Enhance todo-continuation-enforcer to inject prompts BEFORE session.idle
- Pass BackgroundManager to todo-continuation-enforcer for task status checks

This fix prevents `opencode run` from exiting prematurely when work is pending.

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/non-interactive-env/index.ts

@@ -3,6 +3,7 @@ import { HOOK_NAME, NON_INTERACTIVE_ENV, SHELL_COMMAND_PATTERNS } from "./consta
 import { log } from "../../shared"
 
 export * from "./constants"
+export * from "./detector"
 export * from "./types"
 
 const BANNED_COMMAND_PATTERNS = SHELL_COMMAND_PATTERNS.banned