Add invite and promo landing pages

[JonnyLuca]

Summary / Zusammenfassung

EN. Invite and promo landing pages on realunit.app (Offerte Entwurf 3, point 3): public lookup, store badges, copy, Universal Links / App Links, Play Install Referrer. Language × device × state visuals are covered; no further permutations.

DE. Einladungs- und Promo-Landings auf realunit.app (Offerte Entwurf 3, Ziff. 3): öffentlicher Lookup, Store-Badges, Kopieren, Universal Links / App Links, Play Install Referrer. Sprache × Gerät × Zustand visuell abgedeckt; keine weiteren Permutationen.

Scope, measurements, blockers

Scope

• /invite/{code} personal greeting from public lookup; /promo/{code} campaign text (promo Aktionstext 1:1).
• Public lookup GET /v1/realunit/referral/code/:code consumes backend inviterName / inviteeName (CORS on realunit.app). NestJS unmounted Cannot GET is unavailable, not invalid.
• Universal Links / App Links: AASA + Digital Asset Links as HTTP 200 on apex and www (no 301 on .well-known/). Extra AASA alias /apple-app-site-association as HTTP 200 (www included).
• GitHub release APK SHA-256 7F:8B:14:54:E2:91:E9:DB:56:21:69:0A:64:23:7C:34:80:78:C6:5B:B4:86:31:CA:02:9D:14:20:E6:3C:7B:40 (O=DFX AG, CN=Konstantin Ullrich).
• Store badges, copy code/link, iOS re-tap hint, Android Play Install Referrer (attached during lookup).
• Playwright tests/site.spec.mjs + tests/behavior.spec.mjs + tests/visual.spec.mjs. Visual matrix in tests/pages.mjs (invite/promo × ok/loading/invalid/unavailable/spent/missing-code/fallback × DE/EN × desktop/tablet/iOS/Android as applicable). Baselines via e2e:docker:update only.

Measured 2026-08-30 (clean checkout of current PR head 4d79bc0)

Check	Result
npm run check on native host	Prettier OK; html-validate OK; check-site 6 HTML / 54 refs; vitest 144/144; 100% lines/statements/branches/functions
npm run e2e:docker:update (approved baseline refresh)	234 passed, 282 project-inapplicable skipped, 0 failed in 1.1m; exactly 33 changed baselines visually reviewed
Native WebKit launch (webkit-2311)	blocked: inspector-pipe timeout after 60s, reproduced after forced 77.2-MiB browser reinstall and with both Xcode and CLT developer dirs
npm run e2e:docker after refresh	234 passed, 282 project-inapplicable skipped, 0 failed in 1.1m; check-visual 112/112 view × project baselines present
Repository hygiene	clean checkout; no package or lockfile changes

Open blockers

• WebKit: Playwright launch on this Mac times out (see above); native app iPhone/macOS E2E is green in app #942.
• Backend rollout: draft DFXswiss/backend#5290 implements and tests the matching lookup route and fields; live deployment remains human-owned.
• Human: merge this PR so production realunit.app AASA, assetlinks and /invite/* stop 404ing.
• Human: Play App Signing fingerprint if it differs from the GitHub APK.

Related: RealUnitCH/intern#3 (do not auto-close).

[JonnyLuca]

Fixes RealUnitCH/intern#3

Store badges and Play Store install referrer added on /invite and /promo.