fix(providers): show a No Auth provider's real requirement on its banner

[HouMinXi]

Summary

• The No Auth section showed every provider the same banner, saying it was ready to use with no signup and no API key. That is wrong for providers that need a local component, a browser binary or a matching client.
• The real requirement was already written in each provider's notice in noauth.ts. The banner now appends that notice when one exists, and a provider without one keeps the original banner.
• No new copy was written.

Related Issues

• Closes fix(providers): the No Auth banner says 'ready to use immediately, no signup or API key' on providers that need a local component, a browser binary or a client contract #15326

Validation

• Change type: other (dashboard banner)
• Focused tests: node --import tsx/esm --test tests/unit/noauth-banner-requirement.test.ts (3 pass)
• eslint on the changed files, with the repo suppression file
• Reconciled with release/v3.8.52 @ 23a1148486
• New test covers the change
• Defect injection: removing the two resolver calls turns the cloudflare and opencode cases red while the duckduckgo case stays green, and the change was restored

Tests Added Or Updated

• tests/unit/noauth-banner-requirement.test.ts (added)

Coverage Notes

• The test checks a provider with a notice, a provider without one, and the account card path.

Reviewer Notes

• authHint is not used. Only notice.text is appended, because that is the field that states a hard prerequisite.