Confirm ticket pricing tiers before making them public

Context

PR #111 added visible prose on the homepage and a new key-questions.html partial that display the ticket price range using the values from hugo.toml:

• Student: €40
• Early Bird: €70
• General: €100
• Corporate: €300

These values are currently shown on the homepage as: "Tickets from €40 to €300" and in the Q&A section: "Tickets range from €40 (student) to €300 (corporate)."

They are also referenced in the Event schema AggregateOffer (lowPrice / highPrice).

Problem

The ticket pricing has not been officially confirmed or announced. Publishing these figures before the team agrees on them could be misleading to attendees and sponsors.

Questions to resolve

• Are the current price tiers (€40 / €70 / €100 / €300) confirmed for 2026?
• When will ticket sales open (needed to update ticketsUrl in hugo.toml and switch AggregateOffer.availability from PreOrder to InStock)?
• Should the prices be hidden from the homepage until sales open, or is showing them now acceptable?

Options

1. Confirm prices as-is — merge PR #111 as-is once prices are agreed
2. Hide prices until sales open — comment out the ticket price display in key-questions.html and the key-facts bar until Tito/ticketing is set up
3. Show placeholder wording — replace "€40 to €300" with "TBA" or "from €X" once a minimum price is confirmed

Review PR #111, hugo.toml, key-questions.html, the homepage key-facts bar, and the Event schema AggregateOffer. First confirm the team's decision on the 2026 tiers, sales timing, and whether prices should be public; done means the selected option is consistently reflected in those locations.