Add phone number formatter for readability and unit test

[ericksondelacruz]

Summary

• Added formatPhoneNumber utility that formats Philippine phone numbers by digit length: mobile (09XX XXX XXXX), Metro Manila with area code ((02) XXXX XXXX), provincial landline ((0XX) XXX XXXX), and Metro Manila 8-digit local (XXXX XXXX). Unrecognized formats (short codes, legacy 7-digit) are returned unchanged.
• Applied formatPhoneNumber to hotline card display labels for both primary and alternate numbers.
• Fixed handleCall to strip non-digits before building the tel: URI, preventing RFC 3966-invalid links for numbers stored with dashes (e.g. 552-1160).
• Added vitest and a test suite for formatPhoneNumber covering all four formats with hand-crafted cases plus data-driven tests against the full public/data/hotlines.json (759 numbers across 5 format categories).

Test plan

• Run npm test — 10 tests pass
• Open the app and verify hotline numbers display with
  proper spacing/grouping on cards
• Tap a hotline button on mobile and confirm the call
  dialer opens with a clean number (no dashes or spaces)
• Verify alternate numbers in the modal also display
  formatted and dial correctly

[vercel]

@ericksondelacruz is attempting to deploy a commit to the waffenffs' projects Team on Vercel.

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