Track remaining work for the shared Rust core integration on iOS

[pgherveou]

Context

Track the remaining work to land the initial Rust integration , complete the migration to the shared Rust core, and address the main production-readiness gaps.

other references: https://hackmd.io/rNkC3LdOSpy4yL--s1XoBw

Initial integration blockers

• Permission-gating:
  • Outbound network requests
  • WebRTC access inside the container
• Add Extrinsic V5 support TrUAPI #333.
  • Related WIP PRs: frame-decode #104, Subxt #2268.
  • Encode the transaction-extension pipeline version from metadata rather than a constant — #382, merged as 0b1ae564. Raised by @kianenigma below: mainnet keeps two extension pipelines, and the allowance builder wrote a hardcoded 0x00 while selecting its extension set by extrinsic-format version. Both the extrinsic body and the ring-VRF proof message now carry the version the runtime declares.
• Make sure that PGAS allowances are supported.
  • Claim on Asset Hub, shared by the direct and SSO allocation paths — #391, merged as f0761139. Live-verified against paseo-next-v2 Asset Hub.
  • truapi-host-cli serves Asset Hub as a chain role, so the claim is reachable from a host — #404, merged as d88d3414.
  • supported_chains must return Asset Hub from dotli, iOS, and Android before products see anything but NotAvailable.
• Statement store allowances: when no slot are available - Native replace the oldest one that can be replaced and replace it, rust does not. — #378, merged as b5734119. Replaces the oldest slot past Resources.StmtStoreReplacementCooldown, aged against the chain's clock rather than the host's, and reports exhaustion only when nothing is replaceable.
  • NOTE: this covers choosing the victim. When nothing is replaceable the core reports exhaustion but nobody acts on it — the host CLI rotates its auto-managed account, the renewal loop only logs a warning, and a product gets a bare NotAvailable. The core→host exhaustion signal is tracked as a #308 follow-up.
• Complete Chat modality support (#326, specification).
• Build and packaging. Swift framework artifacts should be published so that the app can be outside of the current submodule
• SignVRF not implemented on Android (Tarik's breakdown)

Full integration follow-up

• Move SSO to the shared Rust core. Related work: polkadot-app-ios-v2#1313.
• Implement RFC 0017 in Rust.
• Route payment functions and subscriptions for products such as T3rminal through the native/shared core, or add temporary callbacks for payment subscriptions.
• Add background processing for statement-store allowance renewal (#308) and Coinage.
  • Renewal engine, target ledger, and periodic driver — #308, merged as f54d0c5c. Targets persist in CoreStorageKey::StatementRenewalTargets as derivation recipes; live-verified against paseo-next-v2.
  • Export the renewal entry points over UniFFI and drive them from an OS worker (WorkManager / BGTaskScheduler). Not reachable from iOS or Android today — see Drive statement-store allowance renewal from a host OS scheduler #376.
  • Coinage background processing — #344.

Performance and resilience

• Investigate the PAPI provider memory issue when the app is backgrounded. @ERussel to provide details.
• Support background execution for in-flight async work such as extrinsic submission, using a Rust callback/task abstraction. @ERussel to provide details.
• Revalidate OS permissions before each protected operation because the host or OS may suspend, revoke, or reset them.
• Add diagnostics that notify the user when an operation takes too long.

[kianenigma]

Add Extrinsic V5 support #333.

I don't know how this is managed, but on mainnet, unlike all testnets, we want to keep two versions for transaction extensions. I believe this implies encoding an extra "extension pipeline version" in the transactions: polkadot-fellows/runtimes#1233 (comment)

It is something you need to keep in mind, if you are "manually" building extrinsics, vs. fully relying on metadata. I remember at least for some time, people were building v5 extrinsics manually, hardcoding some metadata stuff.

Just an FYI. Please comment in polkadot-fellows/runtimes#1233 (comment) if any support needed.

[TarikGul]

Currently pushing the allowances to completion. Finishing #308 - along with PGAS allowance, and statement store allowance when slot are not available.

[ERussel]

Unchecked for now "Route payment functions and subscriptions for products such as T3rminal through the native/shared core, or add temporary callbacks for payment subscriptions.". I think we need temporary callbacks for payments calls