Add timezone search to user settings

[akmhatey-ai]

Summary

• Add a searchable timezone input above the user settings timezone select
• Filter friendly timezone options by city, region, or UTC offset while keeping the current selected timezone available
• Add LiveView coverage for the filtered timezone options

Closes #152.

Validation

• mix format --dot-formatter C:\Users\akmha\Money\scripts\plain-elixir-formatter.exs --check-formatted lib\algora_web\components\timezone_select.ex lib\algora_web\live\user\settings_live.ex test\algora_web\live\user_settings_live_test.exs
• MIX_ENV=test mix compile --warnings-as-errors
• MIX_ENV=test mix test test/algora_web/live/user_settings_live_test.exs
• git diff --cached --check
• gitleaks detect --pipe --redact --verbose --no-color

Notes

• The focused WSL test logs existing ChromicPDF startup noise in this environment, but it completed with 1 test, 0 failures.
• I did not run the full test suite.