feat: add SMTP settings edit for IMAP sources in campaigns

[baderdean]

Summary

• Add SMTP fields (smtpHost, smtpPort, smtpSecure) to IMAP credentials interface
• Email-campaigns edge function now uses saved SMTP settings before auto-detecting
• After guessing SMTP, saves detected settings to database for future use
• Add PUT endpoint for updating IMAP credentials in backend
• Add edit SMTP UI in sources page (IMAP sources only - Google/Azure are read-only)

How it works

1. First campaign send: System auto-detects SMTP → saves to DB
2. Subsequent sends: Uses saved SMTP from credentials, no guessing needed
3. Manual edit: Click "Edit SMTP" button on IMAP sources to update settings

Files changed

• backend/src/db/interfaces/MiningSources.ts - Add SMTP fields
• backend/src/routes/mining.routes.ts - Add PUT endpoint
• frontend/src/pages/sources.vue - Edit SMTP dialog for IMAP sources
• frontend/src/types/mining.ts - Add SMTP fields to type
• supabase/functions/email-campaigns/index.ts - Use and save SMTP settings

Testing

• Verify IMAP sources show "Edit SMTP" button
• Verify SMTP settings are saved after first campaign send
• Verify subsequent sends use saved SMTP settings

[github-actions]

Coverage Report

✅ Passed

Commit: cad408f

Summary

	Name	Stmts	Branch	Funcs	Lines
🟡	Total	44.1%	43%	50.1%	44.3%

All files

	Name	Stmts	Branch	Funcs	Lines
🔴	backend/src/routes/mining.routes.ts	0%	100%	0%	0%

No coverage changes

	Name	Stmts	Branch	Funcs	Lines
🔴	backend/src/routes/mining.routes.ts	0%	100%	0%	0%

Generated by Test Coverage Reporter for commit cad408f