Add Redis keepalive task, fix Qovery Redis env parsing, and bump version

[vantough]

Motivation

• Prevent managed/free Redis instances from being marked inactive by periodically touching a key.
• Fix Qovery Redis environment variable parsing so Redis can initialize correctly on that platform.
• Start the keepalive mechanism automatically on bot startup/restart.
• Reflect the change with a version bump.

Description

• Added keep_redis_alive() in pyUltroid/startup/funcs.py:
  • runs only when current DB backend is Redis
  • writes key KEEP_ACTIVE with a UTC timestamp value
  • uses REDIS_KEEPALIVE_INTERVAL if set, otherwise defaults to 7 days
  • enforces a minimum interval of 60 seconds
• Wired startup scheduling in pyUltroid/__main__.py via:
  • importing keep_redis_alive
  • ultroid_bot.loop.create_task(keep_redis_alive()) after startup init
• Fixed Qovery env parsing bugs in pyUltroid/startup/_database.py:
  • vars → vars_
  • vars_.endswith("_HOST")
  • if hash_: (instead of undefined hash)
• Bumped pyUltroid/version.py:
  • __version__ = "2026.04.03"
  • ultroid_version = "2.1.2"

Testing

• python -m compileall pyUltroid