Render every speaker for co-hosted keynote sessions

[JacobCoffee]

Summary

Session detail pages for co-hosted keynote sessions (e.g. "Rachell Calhoun & Tim Schilling") were only showing one speaker. The enrichment loop stopped at the first matching keynote speaker in `keynoteSpeakers`:

for (const [name, data] of Object.entries(this.keynoteSpeakers)) {
  if (sessionName.toLowerCase().includes(name.toLowerCase())) {
    this.keynoteData = { name, ...data };
    break;  // <- only the first hit
  }
}

For the Sun 3:15 pm slot, iteration hit Tim Schilling first, set `keynoteData` to Tim, and broke — Rachell Calhoun never made it to the template.

Fix

• `keynoteData` is now an array of every matching keynote speaker.
• Template `ngFor`s the speaker card so all matches render.

Test plan

• Rachell Calhoun & Tim Schilling session detail — both speaker cards render
• Single-speaker keynote sessions (Lin Qiao, amanda casari, Pablo Galindo Salgado) still render one card
• Non-keynote sessions unchanged

[JacobCoffee]