feat(competitions): require 3 distinct source links per competition (fixes #268)

[shauryagangrade]

What this changes

Every competition record must now point at 3 distinct source URLs, and the
dataset has been updated so all 130 records satisfy it. This resolves #268, which
asked for a minimum of three links per competition.

Closes #268

Summary

The problem. The schema already required organizer_url, official_url and a
source_url per date, but nothing stopped a record from reusing the same page
for all of them. A competition linking to a single site looked like it had three
links, while really being one link deep. Spot check before this change: ~20
records collapsed all URLs onto one page.

The fix.

1. scripts/validate-competitions.mjs - new check that collects every URL on a
   record (organizer, official, every date source, and country track
   official/stage sources), normalizes them (http/https, leading www.,
   trailing slash, hash fragment), and requires at least 3 distinct pages.
   Different pages on the same site count; identical pages do not.
2. src/lib/validate-competitions.test.ts - regression test that builds a record
   where official_url collapses onto organizer_url and asserts the validator
   rejects it. This test fails against the pre-fix script and passes with it.
3. data/competitions/*.json - diversified source URLs across all 15 files so
   every record now points at 3+ distinct pages, using real pages on the same
   site (rules, FAQ, schedule, registration, results pages) rather than invented
   ones.

Root cause

The validator enforced URL fields individually but never cross-checked them, so
no feedback loop existed for a record that was only one link deep. That is the
gap #268 targets.

Verification

Ran the project's full check pipeline on this branch:

• npm run validate:competitions - all 15 files, 0 errors
• npm run test:unit - 47 files, 439 tests passed (includes the new regression test)
• npx tsc --noEmit - no errors
• npm run lint - clean
• npx prettier --check data/competitions scripts/validate-competitions.mjs src/lib/validate-competitions.test.ts - clean

Notes (small bundled fix, decision documented)

While diversifying the math URLs the data was checked against the MAA's official
2026-27 schedule, which surfaced two stale entries that were corrected in the
same files:

• AMC 10/12 A and B moved to the published dates (Nov 5 / Nov 13, 2026) and are
  now marked estimated: false, sourced from maa.org.
• The USAMO entry previously claimed 2027-03-24; MAA's published 2027 policy
  documents state March 20-21, 2027, so the entry is corrected to day 1 of 2
  (March 20) with the official policy PDF as its source.

Happy to split these out into a separate commit if preferred - they were a
consequence of re-verifying the math category's sources rather than a separate
intent.

Type of change

• Code or fix
• New public place(s)
• New or updated benefit guide
• New or updated resource link
• Docs

Checklist

• The changes host no copyrighted files (links only; no image or media files added)
• No em dashes in any copy
• The affected tests pass and the full unit suite is green

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Project	Deployment	Actions	Updated
study-map	Ready	Preview	Sep 19, 2026 7:14am UTC