feat(expo-hall): replace floor plan with 2026 layout, tappable booths…

[JacobCoffee]

(PYMOBIL-65)
Drop the hard-coded 2025 booth grid and ship the new 2026 expo hall:

• New floor plan image (pycon-us-2026-floorplan-nologo.png, 8000x5655)
  with no baked-in sponsor logos — we render the logos as overlays so
  they stay in sync with the API.
• Booth coordinates moved into a typed BoothData[] array on the
  component (top/left/width/height in original-image px); each row's
  ngStyle scales them to percentages.
• ConferenceData.getSponsors() merges logo_url, level, description,
  and the canonical sponsor name onto matching booths by booth_number.
• Tap shows a bottom-sheet popup with name, booth #, and level. When
  the booth matched a sponsor, the popup row is a routerLink to
  /app/tabs/sponsors/sponsor-detail/ using the existing slug
  scheme so users can drill into description + job listings.
• Search bar in the toolbar filters by name or booth number, with a
  results dropdown that scrolls the map to the selected booth and
  pulses a highlight.

Drop the unused expo-hall.page.spec.ts (placeholder, never wired into
CI). Keeps the toolbar update-button pattern from PYMOBIL-113.

Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com