feat(ios): add VoIP push support for PushKit / CallKit

[yash-garg]

Closes FM-638

I've tested this with the app and it works, the call shows up natively in iOS.

[codecov]

Codecov Report

❌ Patch coverage is 77.41935% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.83%. Comparing base (b97ce1d) to head (80408d6).

Files with missing lines	Patch %	Lines
src/pusher.rs	78.04%	9 Missing ⚠️
src/error.rs	0.00%	4 Missing ⚠️
src/models.rs	94.11%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
- Coverage   90.17%   88.83%   -1.34%     
==========================================
  Files           9        9              
  Lines         529      591      +62     
==========================================
+ Hits          477      525      +48     
- Misses         52       66      +14     

Files with missing lines	Coverage Δ
src/api.rs	96.87% <ø> (ø)
src/settings.rs	91.30% <ø> (ø)
src/models.rs	96.52% <94.11%> (-0.42%)	⬇️
src/error.rs	66.66% <0.00%> (-10.26%)	⬇️
src/pusher.rs	93.38% <78.04%> (-2.92%)	⬇️

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[Copilot]

Pull request overview

Adds first-class support for iOS VoIP pushes (PushKit/CallKit) by introducing a dedicated VoIP APNs push path and routing data_message: ios_voip devices through it, with accompanying tests and config documentation updates.

Changes:

• Add DataMessageType::IosVoip and route VoIP devices through direct APNs regardless of notify_via.
• Implement push_notification_voip_apns to send APNs requests with apns-push-type: voip and CallKit-related custom payload fields.
• Add test coverage for VoIP payload generation and fallback behavior when sender_display_name / event_id are missing.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/models.rs	Introduces IosVoip device message type detection via data_message: ios_voip.
src/api.rs	Routes VoIP pushes to direct APNs and calls the new VoIP pusher function.
src/pusher.rs	Adds VoIP-specific APNs push function and blocks VoIP from going through FCM.
src/settings.rs	Allows parsing apns_push_type: voip from config.
src/error.rs	Adds From<a2::Error> mapping to HedwigError for APNs payload/build errors.
tests/pusher.rs	Adds tests validating VoIP payload fields and fallback behavior.
config.sample.yaml	Documents VoIP routing behavior and required APNs configuration.
Cargo.toml / Cargo.lock	Adds uuid dependency for generated call IDs when event_id is absent.

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[FrenchGithubUser]

This will lead to retrying the request push_max_retries times. You could do something like:

impl ErrCode {
      /// Whether retrying a push that failed with this code could ever succeed.
      #[must_use]
      pub fn is_permanent(&self) -> bool {
              matches!(self, ErrCode::BadJson | ErrCode::VoipNotSupported | ErrCode::APNSNotConfigured)
      }
}

And use it to avoid retrying such requests that will just fail every time

[FrenchGithubUser]

this check is already done in 2 other places, I think it's worth extracting it into a small helper and use it everywhere now