feat: native app links for passkeys (#12580)

# Which Problems Are Solved

- Native iOS/Android passkeys need OS trust files on the ZITADEL domain;
without them, Associated Domains / App Links verification fails.
- Operators could not configure iOS Team ID + Bundle ID or Android
package name + SHA-256 fingerprints on OIDC apps.
- `/.well-known/apple-app-site-association` and
`/.well-known/assetlinks.json` were not served from application config.

# How the Problems Are Solved

- Add iOS/Android app-link fields on OIDC app create/update (Application
API v2 + Management), with validation.
- Persist and project those fields; query active app-link configs
instance-wide.
- Serve AASA (`webcredentials`) and Digital Asset Links
(`get_login_creds`) from well-known paths, with configurable
`Cache-Control` and fingerprint normalization at serve time.
- Console UI to edit the fields, with links to the well-known endpoints.
- Operator docs for configuration, endpoints, caching, and verification.

# Additional Changes

- Document on API fields that well-known responses may be HTTP-cached
and platform verifiers may delay propagation.
- Runtime config: `WellKnown.AppLinksCacheControlMaxAge` (default `5m`;
`0` → `no-store`).

# Additional Context

- Closes #12497
- Implemented and reviewed as stack:
  - #12531 API contract
  - #12532 storage wiring
  - #12536 well-known endpoints
  - #12537 console
  - #12547 docs

---------

Co-authored-by: Cursor <[email protected]>

apps/docs/content/concepts/features/passkeys.mdx

@@ -35,5 +35,6 @@ Imagine signing in without passwords! Passkeys, replacing traditional passwords,
 * Passkey support is still evolving in browsers and platforms. Check compatibility for your target audience.
 * ZITADEL actively develops its passkey features. Stay updated with documentation and releases.
 * Passkeys are bound to your domain, thus we recommend configuring a [Custom Domain](/concepts/features/custom-domain) before setting up passkeys.
+* Native iOS and Android apps that use platform passkey APIs also need domain association files. Configure them on the OIDC app and let ZITADEL serve the well-known documents — see [Native app links for passkeys](/guides/integrate/login/oidc/native-app-links).
 
 Don't hesitate to ask if you have further questions about integrating passkeys in your ZITADEL application!