fix(events/org): patch event creation API and organizer deletion

[Sak1012]

These PR has the following changes

• Set a default create_for='all' so API-created events correctly show the Talks navigation and dashboard.
• Fix organizer deletion timeouts by detaching queued mail references before deleting event mail templates.
• Unblock organizer deletion by clearing protected team API token log references and adding deletion-stage logs for debugging.

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[Copilot]

Pull request overview

This PR adjusts default event settings to ensure API-created events behave consistently in the UI, and hardens organizer/event deletion flows to avoid protected-relation failures and provide better operational visibility during deletions.

Changes:

• Add a default create_for='all' setting so events created without explicit configuration still expose Talks-related navigation.
• Improve organizer deletion reliability by clearing LogEntry.api_token references before deleting teams/tokens, and add deletion-stage logging.
• Reduce deletion failures/timeouts by detaching queued mail references before deleting event mail templates, plus add deletion-stage logging in event cleanup.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
app/eventyay/control/views/organizer_views/organizer_view.py	Adds start/finish and protected-relation logging around organizer deletion.
app/eventyay/base/settings.py	Adds create_for default and minor formatting cleanup for serializer helpers / validation blocks.
app/eventyay/base/models/organizer.py	Adds deletion-stage logs and clears protected LogEntry.api_token references prior to team deletion.
app/eventyay/base/models/event.py	Adds deletion-stage logs; detaches queued mail → template references before deleting mail templates; adjusts stored file deletion query.