polish: minor ux and code quality improvements #7

miscellaneous improvements #

collection of smaller issues that would improve code quality and ux:

1. no shared constants #

magic strings repeated across files:

• api endpoints (https://public.api.bsky.app/xrpc/...)
• local storage keys (atme_did, atme_onboarding_seen, atme_atmosphere)
• namespace splitting logic

2. missing error handling #

several places with silent failures:

• app.js:29-36 catches and continues silently
• login.js:94-96 silent continue on fetch failure
• could show user feedback when discovery fails

3. responsive sizing magic numbers #

lots of hardcoded sizing throughout:

• app.js:183 radius calculations
• templates.rs clamp() functions everywhere
• could be more systematic

4. no typescript #

vanilla js is fine, but means:

• no type safety
• no autocomplete
• easier to introduce bugs

priority #

low - these are polish items, not blockers