All page-level headers now use fontSize:1.125rem, fontWeight:700,
color:#0f172a, container py:2.5, borderBottom:#e8e7e4 — matching
the standard established in PageHeader. Removes variant="h5"/h6"
inconsistencies across Supply, Demand, and shared components.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
'Angebot erstellen' button in Marktsignale tab pre-selects the property
in the offer store and navigates to /supply/anfragen on the Latente
Anfragen tab. Also fixes offerWizardStore.open() to preserve
selectedPropertyIds so pre-selection survives the wizard open call.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>