feat: upgrade pubky bindings to 0.10

[pwltr]

Summary

• upgrade pubky to 0.10.0 and update the FFI crate version to 0.4.0
• expose Grant auth as the default sign-in/sign-up binding API while keeping explicit Cookie auth entrypoints
• update auth URL parsing to use pubky::deep_links::DeepLink so signin_grant and signup_grant URLs are accepted by the SDK parser
• add parse_deep_link bindings for the broader pubky deeplink surface, including direct_signup and secret_export
• regenerate Android, iOS, and Python bindings/native artifacts and update the README for the new session-token behavior

Verification

• cargo fmt --check
• git diff --check
• cargo build
• cargo test parse_auth_url -- --test-threads=1
• cargo test parse_deep_link -- --test-threads=1

Note: I also ran the full cargo test locally. The parser/deeplink coverage passed, but the network-dependent tests cannot complete in this sandbox because DHT socket initialization fails with PermissionDenied and poisons shared state.

[pwltr]

@SeverinAlexB @andrei-21 adding you as reviewers since you worked on grant auth

[SeverinAlexB]

I don't have time to review. Andrei didn't work on grant auth. Best would be @86667 or @MCarlomagno.

Also, fyi: https://github.com/pubky/pubky-homeserver/releases/tag/v0.11.0

[pwltr]

In that case please @86667 @MCarlomagno review if you can. Note that generated bindings have already been tested in pubky-ring via pubky/react-native-pubky#39 and pubky/pubky-ring#360. Changes just need a code review for correctness.

[MCarlomagno]

@pwltr Overall LGTM, but AI found something funny

Grant auth URLs are rejected by the SDK’s own parser. start_grant_auth_flow emits pubkyauth://signin_grant?..., but parse_pubky_auth_url only accepts signin and signup.

Which seems like a legit issue, can you check that?

[pwltr]

Drafted for fixes, also noticed missing pubky::deep_links::DeepLink bindings so adding those

[pwltr]

@MCarlomagno The grant auth parser issue should be fixed now: parse_auth_url now delegates to pubky::deep_links::DeepLink parsing and accepts signin_grant / signup_grant in addition to signin / signup.

I also added parse_deep_link bindings for the broader Pubky deeplink surface, including direct_signup and secret_export, and regenerated the Android, iOS, and Python binding artifacts. Functionality retested downstream in react-native-pubky and pubky-ring.