test(infra): vitest globalSetup teardown purges test-port-* leaks

Integration tests use makePort() which writes ports with slug 'test-port-{rand}'
and never cleans up. Result: 17,564 leaked rows in dev that slowed every page
load fetching the port-switcher list (and was contributing to smoke flakes).

Adds tests/global-setup.ts with a teardown() that DELETEs every 'test-port-%'
row plus its dependent rows across 30+ tables in one CTE. Wires it into
vitest.config.ts via globalSetup. Adds closeDb() helper so the teardown can
end the postgres-js pool cleanly (kills the 'Tests closed but Vite server
won't exit' warning).

Also lands docs/superpowers/specs/2026-04-28-country-phone-timezone-design.md
— full-scope agenda for the country dropdown / E.164 phone input /
country-driven timezone autofill work, ~7 dev days across 10 PRs. Per
user request: 'let's do this full-fledged if we're gonna do it'.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vitest.config.ts

@@ -10,6 +10,7 @@ export default defineConfig({
     include: ['tests/unit/**/*.test.ts', 'tests/integration/**/*.test.ts'],
     exclude: ['tests/e2e/**', 'node_modules/**'],
     pool: 'forks',
+    globalSetup: ['./tests/global-setup.ts'],
     coverage: {
       provider: 'v8',
       reporter: ['text', 'lcov', 'json-summary'],