Prompts list accepts invalid page numbers

[forgou37]

The GET /api/prompts endpoint parses the page query parameter without clamping it to a valid range — same issue as the directory and other listing endpoints.

Repro

GET /api/prompts?page=-1

Observed:

• page = parseInt("-1") = -1 (truthy, so || 1 fallback is skipped)
• offset = (-1 - 1) * 20 = -40
• Supabase .range(-40, -21) returns a database error (500)

Fix

Clamp page to a minimum of 1:

const page = Math.max(1, parseInt(url.searchParams.get("page") || "1") || 1);

[Jorel97]

Submitted PR #305 for this: #305

Scope: clamp invalid/non-positive page query values before calculating the Supabase range so /api/prompts?page=-1 falls back to page 1 instead of producing a negative offset.