Fix webhook notifier not reading URL from dashboard config

[dc-larsen]

Summary

• WebhookNotifier.__init__ used self.config.get('url') but the parameter key from notifications.yaml is webhook_url. Dashboard-configured webhook URLs were silently dropped.
• Env var path (INPUT_WEBHOOK_URL) was unaffected, which is why this wasn't caught in earlier testing.
• Aligns with the pattern already used by JiraNotifier (self.config.get('jira_url')).

Root cause

Step	Key used	Source
Manager enablement check	app_config.get('webhook_url')	manager.py:82
Parameter resolution	params['webhook_url']	notifications.yaml name field
Notifier constructor	self.config.get('url')	webhook_notifier.py:22

The constructor looked for 'url' but received 'webhook_url', so self.url resolved to None.

Reproduction

from socket_basics.core.notification.webhook_notifier import WebhookNotifier

# Simulates dashboard config flow (app_config -> params)
n = WebhookNotifier({"webhook_url": "https://hooks.example.com/endpoint"})
print(n.url)  # Before fix: None | After fix: https://hooks.example.com/endpoint

Customer context

Customer configured webhook URL via the Socket dashboard ("Generic webhook URL for notifications"). Logs showed notifier loaded (enabled via app_config:webhook_url) but then logged WebhookNotifier: no webhook URL configured at send time. Jira notifier worked correctly because its config keys are consistent.

Testing

• 7 new tests in tests/test_webhook_notifier_params.py covering:
  • Direct param reading from dashboard config
  • Empty config (no URL)
  • Env var fallback (INPUT_WEBHOOK_URL)
  • Param precedence over env var
  • Full manager flow with app_config
  • Full manager flow with env var
  • Manager precedence (app_config over env)
• Full suite: 98/98 passed