When multiple plugins register for the same provider (e.g., openai), all their
auth methods are now merged into a single list. This allows external plugins
to add auth methods alongside built-in options.

Previously, only the first matching plugin's methods were shown due to .find()
returning the first match. Now we use .filter() to collect all plugins and
flatMap their methods.

The first plugin's loader is still used (internal plugins take precedence),
ensuring backward compatibility.

Use case: Multi-account authentication plugins can add their auth methods
alongside the built-in ChatGPT Pro/Plus option, giving users choice between
single-account and multi-account auth flows.

- Add percentage-based quota recovery calculation (0% = just hit limit, 100% = ready)
- Add visual progress bar display with color coding (green/yellow/red)
- Add web app /accounts dialog component
- Clean up code style and remove redundant comments

- Restore custom-elements.d.ts symlinks that were accidentally replaced
- Replace let with const IIFE for status determination (style guide)

Add /accounts dialog for multi-account management