IAV-1309/ Telephony Agent — UI/UX overhaul across all section views and wizard

Design system — all telephony views

• Applied SAV-inspired glassmorphism tokens consistently across all views: ::before top-40% gradient shine, ::after horizontal sweep on hover, inset 0 1px 0 rgba(255,255,255,0.1) box-shadow, translateY(-4px) hover lift
• Affected: dashboard-section, calls-section, campaigns-section, phone-numbers-section, call-detail-view, calendar-section, assistant-section, integrations-section`

Prospects table (prospects-section.tsx)

• Redesigned to match the assistant table: glass card container (blur(24px), 2px solid, borderRadius: 20px), dark gradient sticky header, translateY(-2px) + ::after shine on row hover - "Nom" column: avatar (square, 36×36) + name bold + phone — identical pattern to the agents table
• Multi-select checkboxes with bulk delete icon in header
• Scrollable body (maxHeight: 520) with thin colored scrollbar
• Empty state with centered icon box

Integrations section (integrations-section.tsx)

• Enforced single-active integration (radio behavior): activating one auto-deactivates all others
• Deactivation blocked when it's the last active integration

Assistant section (assistant-section.tsx)

• Removed inline validation error messages between nav buttons
• "Suivant" disabled instead of showing error text

Dashboard section (dashboard-section.tsx)

• KPI cards redesigned: text (value + label) left, icon right
• Added section title + subtitle

Wizard (telephony-wizard.tsx)

• Edit form now hides the prospect list (same behavior as "Ajouter")
• Removed dead inline ternary from prospect list map
• Prospect rows: fixed height 76px, flexShrink: 0, maxHeight: 428px = exactly 5 rows visible with scrollbar on 6th
• Email column always rendered (— fallback) to prevent layout shifts
• Rejected rows table: glassmorphism redesign with red-themed header, chip-based reasons, close button