fix(sdk): wallet-flow network fixes for SwiftExampleApp

[QuantumExplorer]

Issue being fixed or feature implemented

A set of wallet-flow fixes in the iOS SwiftExampleApp / swift-sdk for operating across multiple networks. The same mnemonic can now live on several networks, and the create / rescan / add-to-network flows behave correctly when the target network isn't the currently-active one.

Bugs fixed:

1. Mainnet/testnet wallet creation silently failed. The devnet-only platformQuorumURL override was applied to every network, leaking a non-https http://… quorum URL into mainnet/testnet SDK construction. Rust's trusted context provider rejects a non-https custom quorum URL on those networks, so the build failed and no wallet was created.
2. Create dialog ignored the ticked network. Ticking e.g. "Mainnet" while on devnet created a devnet wallet instead — only the first/active network was used.
3. No feedback on create failure. The error alert is bound to CreateWalletView, but the pushed SeedBackupView stayed on top with its submit button stuck disabled — the user was stranded with no visible error.
4. Per-network "+" add-to-network did nothing. The button in Wallet Info didn't actually add an existing wallet to another network.
5. Re-scan for Identities showed wallets from all networks. The picker used an unfiltered @Query, listing every wallet across every network instead of just the active-network ones.

What was done?

Per-network persistence infrastructure

• PersistentWallet.swift — make rows unique per (walletId, network) and add predicate(walletId:) / predicate(walletId:network:) helpers, so the same mnemonic can coexist across networks without colliding.
• PlatformWalletPersistenceHandler.swift / PlatformWalletManager.swift — scope persister wallet lookups to the manager's network, so each per-network manager restores only its own rows.

Create flow

• CreateWalletView.swift — create the wallet in every ticked network via WalletManagerStore.backgroundManager(for:) (each network has its own network-locked Rust manager); walletId is network-independent, so the Keychain mnemonic + metadata are written once and isImported is stamped on every per-network row. On failure, pop the pushed backup screen so the error alert becomes visible.
• SDK.swift — gate the platformQuorumURL (and DAPI address) override behind useOverrideAddresses (regtest/devnet or opt-in docker). Mainnet/testnet now use the SDK's automatic canonical quorum endpoints.

Add-to-network / identities / rescan

• WalletDetailView.swift — implement the per-network "+" add-to-network action.
• IdentitiesContentView.swift — take an explicit network and scope the identities @Query to it; IdentitiesView.swift passes the active network; ContentView.swift threads the active network through.
• SearchWalletsForIdentitiesView.swift — add platformState, query all wallets, and filter to the active network via a computed property (mirrors WalletsContentView — @Query can't reference a runtime env-object value at property-init time). The rescan sheet re-injects platformState.

All changes are Swift-side only (persist / load / bridge) — no Rust/FFI changes, no protocol changes.

How Has This Been Tested?

Verified on the booted iOS simulator (iPhone 17 Pro) against the live SwiftData store:

• Create routes to ticked network: a testnet-only create while on devnet produced exactly one networkRaw=1 row and no devnet fallback row.
• Add-to-network: the per-network "+" produced a new per-network row + UI checkmark for the target network.
• Rescan network filter: with currentNetwork = mainnet and 9 persisted wallet rows across 4 networks (mainnet ×1, testnet ×3, devnet ×2, regtest ×3), the Re-scan for Identities picker now lists only the single mainnet wallet — count dropped 9 → 1, matching the active-network set exactly.
• Quorum override: confirmed via boot console that mainnet SDK construction logs no DAPI addresses provided, using defaults for network / Mainnet (no leaked devnet http://…:8080 quorum URL), while the devnet manager still uses its caller-provided quorum URL.
• Create-failure UX: verified the backup screen pops on failure so the error alert is reachable.

Note: this PR does not fix a separate, pre-existing crash in the external dash-spv dependency (SegmentedStorage::get_items() panics on segments with a non-zero first_valid_offset), which causes the Core Sync "Start" button to appear to do nothing on mainnet. Filed upstream at dashpay/rust-dashcore#792.

Breaking Changes

None. Swift SDK / example-app behavior only; no consensus or protocol changes.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone

Summary by CodeRabbit

• New Features

  • Multi-network wallet creation persists wallets per network and saves mnemonics per network.
  • UI respects selected network across Identities, search, and Wallet detail.
  • Wallet detail can enable a wallet on additional networks.

• Bug Fixes

  • Wallet IDs can repeat across networks (now treated as network-scoped).
  • Safer deletion: keychain mnemonic/metadata and cached data are removed only when the last network instance is deleted.
  • Avoids leaking dev/test quorum endpoints into production.