fix: use seconds for service listening polling timeout

[lucasmariano003-wq]

Description

AppiumService.is_listening passes STATE_CHECK_INTERVAL_MS directly to is_service_listening, whose timeout is in seconds. When the service process remains alive but its status endpoint is unavailable, the polling budget is therefore 500 seconds instead of 500 milliseconds.

Convert the interval to seconds, consistently with the service startup path. This restores the intended polling budget; individual HTTP request timeouts and retries are unchanged and may extend the overall call duration.

Validation

• Added a regression that exercises is_listening through the real polling helper with a simulated clock. Before the fix, HTTP503 advanced the clock by 500 seconds; afterward it advances by 0.5 seconds. HTTP200 still returns immediately.
• Local subprocess/HTTP fixture: HTTP503 did not finish within 1.5 seconds before the fix and returned False in 0.503 seconds afterward. HTTP200 returned True in 0.001 seconds.
• All 175 unit tests passed.
• make check passed: Ruff, formatting, and Mypy over 320 source files.
• Both published files were fetched back and their hashes match the tested copies.

OpenAI Codex performed the implementation and local validation for this GitHub account; maintainer review is pending.

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