fix(wallet-gateway-remote): include sign-message and api-keys pages i…

[gjrmacedo]

Problem

Three pages exist under wallet-gateway/remote/src/web/frontend/ and are declared as
valid routes in ALLOWED_ROUTES (core/wallet-ui-components/src/routing.ts), but are
missing from the Vite multi-page rollupOptions.input, so they are never emitted:

• sign-message/
• api-keys/
• api-keys/add/

The source tree has 18 index.html entry points; the build config lists 15.

User-visible impact: signMessage is unreachable over the dApp API

wallet-gateway/remote/src/dapp-api/controller.ts returns

userUrl: `${userUrl}/sign-message/index.html?messageId=${messageId}&closeafteraction`

and @canton-network/dapp-sdk opens that URL in a popup. Because the page is not in the
build output, the popup lands on a 404 and the signing request can never be approved —
signMessage times out for every dApp using a remote Wallet Gateway.

Reproduced against the published artifact, not just the source tree: the
@canton-network/wallet-gateway-remote@1.9.0 tarball (the exact package installed by
ghcr.io/digital-asset/wallet-gateway/docker/wallet-gateway) contains no
dist/web/frontend/sign-message/ directory, and no chunk in dist/web/frontend/assets/
references user-ui-sign-message or getMessageToSign. The gateway serves that directory
with a plain express.static(), so a missing entry point is an unconditional 404.

How it got missed

sign-message/ was added in #1718 (2026-05-18), which wired up the dApp API, the RPC
methods and the Lit component (with unit tests), but did not touch
wallet-gateway/remote/vite.config.ts — a file unchanged since #1520 (2026-03-31).

This is the same class of regression already fixed once in #1045
("fix: include transactions page in build").

Fix

Add the three missing entry points to rollupOptions.input, grouped next to their
siblings (signMessage beside approve; apiKeys/addApiKey beside settings,
following the existing parties/addParty and networks/addNetwork pattern).

Verification

vite build in wallet-gateway/remote now emits 18 pages, matching the 18 entry points
in the source tree (15 before):

dist/web/frontend/sign-message/index.html    0.54 kB
dist/web/frontend/api-keys/index.html        0.52 kB
dist/web/frontend/api-keys/add/index.html    0.54 kB

dist/web/frontend/assets/signMessage-Iwjt8OJB.js   8.04 kB
dist/web/frontend/assets/apiKeys-C0iup1Nz.js       5.68 kB
dist/web/frontend/assets/addApiKey-B09ZOS9_.js     5.91 kB

Notes

• No source or behaviour change — build configuration only.
• The existing unit tests for these pages
  (sign-message/index.test.ts, api-keys/index.test.ts, api-keys/add/index.test.ts)
  already pass; they were simply testing components that never shipped.
• Consider a follow-up guard so a page under src/web/frontend/ that is missing from
  rollupOptions.input fails CI — this is the second occurrence.