[US-003] Password reset via email

[leimo2011]

Epic: EP-01 — User Authentication & Profiles \nPriority: Must Have (M) \nStory Points: 3 \nSprint: Sprint 1\n\n### User Story\nAs a user, I want to reset my password via email so I can recover my account.\n\n### Acceptance Criteria\n- [ ] 'Forgot password' link on login screen\n- [ ] User enters email and receives reset link within 2 minutes\n- [ ] Reset link expires after 1 hour\n- [ ] New password must meet complexity requirements\n- [ ] Confirmation message shown after successful reset\n\n### Technical Notes\n- POST /api/auth/password-reset/ and POST /api/auth/password-reset/confirm/\n- Celery + SMTP for email dispatch