feat(dig-app): WalletConnect support (Sage-parity) — tray right-click connect WC string + manage WC connections

[MichaelTaylor3d]

Task

dig-app supports WalletConnect, matching Sage wallet's WC implementation (https://github.com/xch-dev/sage). Via the tray right-click menu: paste/connect a WalletConnect pairing STRING + manage (list/disconnect) active WC connections. User directive 2026-07-21.

Requirements

• Match Sage's WC implementation — the same WC v2 pairing/session flow + the same Chia WC method set (CHIP-0002 wallet methods: chia_connect / chia_signMessage / chia_sendTransaction / chia_signCoinSpends / etc. as Sage exposes). Study Sage's WC code (github.com/xch-dev/sage) as the reference; match its method surface + behavior so any WC dApp that works with Sage works with dig-app.
• Tray-native UX (no main window): right-click tray → 'Connect WalletConnect' (paste the wc: string) + 'Manage Connections' (list active sessions, disconnect). Fits the tray-only dig-app model (below).
• Signing via the OS-native modal — a WC signing request surfaces through the same OS-native foreground signing modal as all other signing (#950), showing what's being signed.
• Custody: WC signs via the user account's HD wallet keys (dig-user-account), local signing only — keys never leave the app / never enter the engine (#908).

Reference

Sage WC impl (xch-dev/sage — the parity target), #950 (native signing modal — WC requests route through it), the CHIP-0002 window.chia contract (already in the extension — the method semantics), dig-user-account (the wallet keys WC signs with), #908. area:apps.

Priority

High — WC is a major dApp-interop surface (parity with Sage). Part of the dig-app frontend family.

Orchestrator ticket: https://github.com/DIG-Network/dig_ecosystem/issues/908

Moved from DIG-Network/dig_ecosystem#1498 so this repo's own PR can close it with Closes (CLAUDE.md §1.3).
GitHub refuses a private-to-public issue transfer, so the body was copied and comment history
stayed on the original.

[MichaelTaylor3d]

Verification sweep 2026-08-20 — verdict: NOT_STARTED → moving to DIG-Network/dig-app (repo-scoped)

Measured against origin/main of DIG-Network/dig-app at 64656adb (v12.34.1).

Nothing of this exists yet

git grep -niE 'walletconnect|wallet_connect|wc_uri|chia_signMessage|chia_sendTransaction|CHIP-0002'
over origin/main -- 'crates/**' returns no source hits at all — only two incidental binary matches
inside PNG screenshots (crates/dig-app-core/docs/profile-wizard/create-wizard-light-960x900.png,
crates/dig-app-core/docs/wallet-cache/cache-dark-960.png). Cargo.toml carries no WalletConnect /
Reown / sign-client dependency.

Why it is repo-scoped rather than cross-repo

Every prerequisite the body names already lives inside dig-app, so one dig-app PR can close this:

• The OS-native signing modal (#950) exists. crates/dig-app-core/src/confirm/mod.rs:782
fn sign(prompt: &SignPrompt<'_>) -> Option<Self>, with the decoded-transaction requirement pinned
  by confirm/mod.rs:1503
fn sign_with_no_decoded_tx_is_denied_without_ever_showing_a_window().
• Local signing with the account's own keys exists, inside the §908 boundary:
  crates/dig-app-core/src/gateway/local.rs:288
let signature = identity.sign(&user_sign_message(message.as_bytes()))?; with the
  DIGNET-USER-SIGN-v1 domain separation documented at :248, and the profile signer at
  crates/dig-app-core/src/account/residency.rs:195 / :575.
• The remaining work is a WC v2 pairing/session client plus two tray rows — an external crate
  dependency (legal at any level) and dig-app-local UI, not a new cross-repo contract.

What did NOT change

The parity target is still Sage (github.com/xch-dev/sage) and the custody rule is still §908 — keys
never leave the app. Nothing measured here relaxes either.

Moving under epic https://github.com/DIG-Network/dig_ecosystem/issues/908 so a dig-app PR's Closes
can retire it (CLAUDE.md §1.3 — a submodule PR's Closes cannot close a superproject issue).