In-app ledger explorer for party, contract, and update ids

[gabitoesmiapodo]

User story / Problem statement

As a dApp user, I want the party, contract, and update ids the dApp renders to be clickable and resolve to their ledger record, so I can verify what happened without leaving the app. Today they link nowhere unless VITE_EXPLORER_URL points at an external explorer.

Expected outcome

Three routes — /party/:id, /contract/:id, /update/:id — render the record read through the connected wallet session's ledgerApi, plus a search box that resolves a pasted id. Pointing VITE_EXPLORER_URL at the app's own origin makes every existing Identifier link land in-app, with no change to the components rendering them.

Acceptance criteria

• src/pages/Explorer/ holds the three route components, registered in src/routes.tsx
• A reader module beside src/backend/config.ts shares the ledgerApi seam, as LiteBackend does
• Party route reads GET /v2/parties/{party}
• Contract route reads POST /v2/events/events-by-contract-id with an eventFormat body
• Update route reads POST /v2/updates/update-by-id
• Activity list reads POST /v2/updates/flats with an updateFormat body
• Search box routes a pasted id by shape, matching getExplorerLink's detection
• A record the connected party cannot read renders an explanatory empty state, not a crash
• VITE_EXPLORER_URL can resolve to the app's own origin
• .env.example, the architecture.md seam and the README env note updated

Alternatives considered

scan-web-ui expects a super validator's full scan API; a separate proxy backend adds a deployment. The wallet session already carries a token that reads.

Technical notes

Every read needs filtersByParty naming a party the token can read — filtersForAnyParty returns 403. These endpoints require an eventFormat body and reject requestingParties. A contract resolves only for a stakeholder party, else CONTRACT_EVENTS_NOT_FOUND, so coverage is the connected party and the vesting operator, not the network. src/utils/env.ts demands an absolute http(s) URL, so an own-origin EXPLORER needs a per-environment value or a src/utils/config.ts change.