Add shared rainbird device lock and increase calendar timeout

[allenporter]

Proposed change

Rain Bird LNK Wi-Fi modules are extremely resource-constrained and can only reliably handle a single HTTP request at a time. The background coordinators (RainbirdUpdateCoordinator and RainbirdScheduleUpdateCoordinator) run on independent update intervals and can execute overlapping requests concurrently, causing the device to return busy warnings (NAKs) or go unavailable.

This PR:

1. Instantiates a shared asyncio.Lock() (device_lock) inside the config entry's setup to prevent concurrent coordinator requests.
2. Synchronizes updates by wrapping both coordinator background update blocks in async with self._device_lock.
3. Increases the schedule fetch timeout from 20 to 30 seconds (CALENDAR_TIMEOUT_SECONDS = 30) to accommodate slower responses from certain controller models when retrieving calendar/schedule timeline data.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Rain Bird ESP-TM2: integration loads schedule for 22 zones on a 4-zone controller, NAK on overshoot marks entity Unavailable #169672
• This PR is related to issue:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to frontend pull request:

Checklist

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[home-assistant]

Hey there @konikvranik, mind taking a look at this pull request as it has been labeled with an integration (rainbird) you are listed as a code owner for? Thanks!

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[Copilot]

Pull request overview

This PR updates the Rain Bird integration to better handle controller modules that can only process one request at a time by serializing coordinator I/O and extending the schedule fetch timeout.

Changes:

• Create a shared asyncio.Lock() during config entry setup and pass it to both update coordinators.
• Wrap both coordinators’ _async_update_data calls with the shared lock to prevent concurrent polling.
• Increase the schedule/calendar fetch timeout to 30 seconds.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
homeassistant/components/rainbird/coordinator.py	Adds a shared lock to both coordinators’ update paths and increases the schedule fetch timeout constant.
homeassistant/components/rainbird/__init__.py	Instantiates the shared lock during entry setup and wires it into the coordinators.