Add Capacitor support with configurable API base URL

.env

@@ -28,6 +28,7 @@ PUBLIC_SHARE_PREFIX=
 PUBLIC_GOOGLE_ANALYTICS_ID=
 PUBLIC_PLAUSIBLE_SCRIPT_URL=
 PUBLIC_APPLE_APP_ID=
+PUBLIC_API_BASE_URL= # Set to backend origin for Capacitor/native builds (e.g. https://huggingface.co/chat)
 
 COUPLE_SESSION_WITH_COOKIE_NAME=
 # when OPEN_ID is configured, users are required to login after the welcome modal

CAPACITOR_READINESS.md

@@ -0,0 +1,126 @@
+# Capacitor Build Readiness Assessment
+
+**Date:** 2026-03-02
+**Status:** Partially Ready — SPA foundation is solid, backend server still required
+
+## Executive Summary
+
+The chat-ui app has completed the foundational work for Capacitor/Tauri support via the
+"chat-ui in tauri" milestone (9 merged PRs). The static adapter is installed and
+`npm run build:static` produces valid SPA output. However, a running Node.js backend
+is still required — the app cannot function as a standalone client-only mobile app.
+
+## What's Already Capacitor-Ready
+
+| Area                 | Status | Detail                                                                |
+| -------------------- | ------ | --------------------------------------------------------------------- |
+| Static adapter       | Ready  | `@sveltejs/adapter-static` installed, `npm run build:static` works    |
+| SPA routing          | Ready  | `fallback: "index.html"`, `strict: false` configured                  |
+| No +page.server.ts   | Ready  | Zero server-side page load files — all loads are universal            |
+| No +layout.server.ts | Ready  | Zero server layout files                                              |
+| UI components        | Ready  | 80+ Svelte components are pure client-side, zero server imports       |
+| HTML template        | Ready  | Viewport already set for mobile (`maximum-scale=1, user-scalable=no`) |
+| Icons/assets         | Ready  | Multiple icon sizes in `static/`, PWA manifest configured             |
+| TypeScript target    | Ready  | ES2018 — compatible with Capacitor WebViews                           |
+| Theme detection      | Ready  | Dark mode via localStorage + `matchMedia` with proper fallback        |
+
+## Architecture
+
+The Capacitor build is a **hybrid architecture**: Capacitor wraps the static SPA frontend,
+which talks to a remote Node.js backend over HTTPS.
+
+```
+┌─────────────────────────────────┐
+│  CAPACITOR APP (iOS/Android)    │
+│  Static SPA via adapter-static  │
+│  UI components, stores, routing │
+│  Talks to remote API via HTTPS  │
+└──────────────┬──────────────────┘
+               │ HTTPS + Auth Token
+               ▼
+┌─────────────────────────────────┐
+│  NODE.JS BACKEND (unchanged)    │
+│  47 API routes, MongoDB, Auth   │
+│  LLM proxy, MCP, file storage   │
+└─────────────────────────────────┘
+```
+
+## Critical Blockers
+
+### 1. API Client hardcodes origin-relative URLs
+
+**File:** `src/lib/APIClient.ts`
+
+```typescript
+const baseUrl = browser
+	? `${window.location.origin}${base}/api/v2`
+	: `${origin ?? "http://localhost:5173"}${base}/api/v2`;
+```
+
+In Capacitor, `window.location.origin` becomes `capacitor://localhost`, which won't reach
+any backend. The API client needs a configurable base URL (e.g., via `PUBLIC_API_BASE_URL`).
+
+### 2. Root layout makes 6 mandatory API calls on every page load
+
+**File:** `src/routes/+layout.ts`
+
+Calls: `user/settings`, `models`, `user`, `public-config`, `feature-flags`, and
+`conversations`. All 47 server endpoints must be reachable — the app is non-functional
+without them.
+
+### 3. Authentication requires server-side sessions
+
+The `hooks.server.ts` middleware validates sessions via MongoDB on every request. OAuth
+redirects, token refresh, and session cookies all require server mediation.
+
+## Browser API Compatibility Issues
+
+| API                              | Severity | Issue                                              |
+| -------------------------------- | -------- | -------------------------------------------------- |
+| `window.location.origin`         | Critical | Returns `capacitor://localhost` in native context  |
+| Relative fetch URLs              | Critical | `/conversation/[id]` won't resolve without backend |
+| `document.cookie`                | High     | May not work in WebView                            |
+| `MediaRecorder` / `getUserMedia` | High     | Needs Capacitor microphone plugin                  |
+| `ReadableStream.pipeThrough`     | High     | Some Android WebViews lack support                 |
+| `localStorage`                   | Medium   | Works but no encryption, cleared on app updates    |
+| Hardcoded `huggingface.co` URLs  | Medium   | Fail offline, can't be overridden                  |
+
+## Remaining Work
+
+| Task                           | Effort | Detail                                                 |
+| ------------------------------ | ------ | ------------------------------------------------------ |
+| Make API base URL configurable | Small  | Add `PUBLIC_API_BASE_URL` to `APIClient.ts`            |
+| Add CORS for Capacitor origin  | Small  | Backend must accept `capacitor://localhost`            |
+| Handle cookie-less auth        | Medium | Bearer token auth or WebView cookie jar                |
+| Add `capacitor.config.ts`      | Small  | Point `webDir` to static build output                  |
+| Install Capacitor packages     | Small  | `@capacitor/core`, `@capacitor/cli`, platform packages |
+| iOS safe area CSS              | Small  | `env(safe-area-inset-*)` for notch/home indicator      |
+| Voice recording plugin         | Medium | Replace raw `getUserMedia` with Capacitor plugin       |
+| Test streaming on Android      | Medium | Verify `ReadableStream` + `TextDecoderStream`          |
+| Handle deep links for OAuth    | Medium | Register URL scheme for login redirect                 |
+
+## Prior Art
+
+### Merged PRs (SPA foundation)
+
+- **#2059** — Dual adapter support (Node + Static) via `ADAPTER=static`
+- **#2058** — Converted last server loads to universal loads
+- **#1699** — Replaced all server-side load functions with universal loads
+- **#1698** — Replaced all form actions with API endpoints
+- **#1743** — New API & universal load functions
+- **#1700** — Ensured the app works as SPA
+
+### Closed PR
+
+- **#2046** — Direct Capacitor iOS PR (closed, superseded by modular approach above)
+
+### Open Issues
+
+- **#1722** — Request for native Android app on Play Store
+- **#1832** — Request for iPad/Mac layouts of App Store app
+
+## Estimated Effort
+
+**1-2 weeks** to get a working Capacitor build, assuming a deployed backend is available.
+The team's stated direction is Tauri rather than Capacitor, but the SPA infrastructure
+supports both equally.

capacitor.config.ts

@@ -0,0 +1,9 @@
+import type { CapacitorConfig } from "@capacitor/cli";
+
+const config: CapacitorConfig = {
+	appId: "co.huggingface.chat",
+	appName: "HuggingChat",
+	webDir: "build",
+};
+
+export default config;