fix(theme): API key white text on white background (#1584)

When generating an API key with the black theme active, the key was
displayed with white text on a white background. This was caused by
hardcoded light-theme classes (`bg-gray-50` and `border-gray-200`) on
the `Input` component that displays the key.

This change removes the hardcoded background and border color classes,
allowing the themed styles to be applied correctly.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- Refactor
- Consolidated common UI and form components behind single import entry
points, simplifying usage and making components easier to discover. No
functional changes.
- Style
- Refined API key input appearance for a cleaner, less intrusive look
while preserving readability and existing controls (copy, visibility
toggle, read-only).
- Chores
- Streamlined component import paths to improve developer experience and
consistency across the app. No user-facing behavior changes.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

web/components/ApiKey/ApiKeyManager.vue

@@ -169,7 +169,7 @@ async function copyKeyValue(keyValue: string) {
                 <div class="relative w-64">
                   <Input
                     :model-value="showKey[key.id] ? key.key : '••••••••••••••••••••••••••••••••'"
-                    class="w-full font-mono text-base px-2 py-1 bg-gray-50 border border-gray-200 rounded pr-10"
+                    class="w-full font-mono text-base px-2 py-1 rounded pr-10"
                     readonly
                   />
                   <button