Decouple bundled UI from runtime API and add remote instance tooling (#1228)

Add a packaged-client runtime boundary so the shared UI can talk to local,
desktop, remote, and VS Code runtimes through the right transport instead of
assuming one same-origin web server.

Centralize OpenChamber-owned API access behind RuntimeAPIs, runtimeFetch, and
runtime URL helpers, while keeping official OpenCode traffic on the SDK path.
Support runtime switching, remote host selection, desktop client credentials,
and headless connection links for pairing packaged clients with remote
OpenChamber servers.

Harden the new auth model by moving long-lived client tokens out of browser
URLs, introducing short-lived scoped URL tokens for browser-owned transports,
restricting URL-token access to explicit readable/realtime routes, and making
client-token management session-scoped or self-scoped as appropriate.

Update browser-owned assets and preview proxy flows to work with the split
runtime model, including authenticated project icons, preview token propagation,
CSP-safe preview bridge injection, and preview proxy auth that survives
short-lived URL-token expiry.

Tighten Electron security boundaries for packaged clients by gating privileged
preload state to trusted origins and requiring explicit confirmation before
connect deep-links import or switch remote runtimes.

Also refresh agent guidance and project skills so future runtime/API, auth,
preview, UI, CLI, settings, locale, and drag-to-reorder work follows the new
architecture.

packages/web/server/lib/opencode/proxy.js

@@ -123,6 +123,61 @@ export const registerOpenCodeProxy = (app, deps) => {
     realpath: fs?.promises?.realpath?.bind(fs.promises),
   });
 
+  const hasParsedBodyValue = (body) => {
+    if (body === undefined || body === null) return false;
+    if (Buffer.isBuffer(body)) return body.length > 0;
+    if (typeof body === 'string') return body.length > 0;
+    if (Array.isArray(body)) return body.length > 0;
+    if (typeof body === 'object') return Object.keys(body).length > 0;
+    return true;
+  };
+
+  const getContentType = (proxyReq, req) => {
+    const value = proxyReq.getHeader?.('content-type') ?? req.headers?.['content-type'] ?? '';
+    if (Array.isArray(value)) return value[0] || '';
+    return String(value || '');
+  };
+
+  const serializeUrlEncodedBody = (body) => {
+    if (!body || typeof body !== 'object' || Buffer.isBuffer(body)) {
+      return String(body ?? '');
+    }
+
+    const params = new URLSearchParams();
+    for (const [key, value] of Object.entries(body)) {
+      if (value === undefined || value === null) continue;
+      if (Array.isArray(value)) {
+        for (const entry of value) {
+          if (entry !== undefined && entry !== null) params.append(key, String(entry));
+        }
+        continue;
+      }
+      params.append(key, String(value));
+    }
+    return params.toString();
+  };
+
+  const serializeParsedBody = (req, proxyReq) => {
+    if (req.method === 'GET' || req.method === 'HEAD') return null;
+    if (req.body === undefined || req.body === null) return null;
+    const originalContentLength = Number.parseInt(req.headers?.['content-length'] || '0', 10) || 0;
+    if (!hasParsedBodyValue(req.body) && originalContentLength <= 0) return null;
+
+    const contentType = getContentType(proxyReq, req).toLowerCase();
+    if (Buffer.isBuffer(req.body)) return req.body;
+    if (contentType.includes('application/json')) return Buffer.from(JSON.stringify(req.body));
+    if (contentType.includes('application/x-www-form-urlencoded')) return Buffer.from(serializeUrlEncodedBody(req.body));
+    if (typeof req.body === 'string') return Buffer.from(req.body);
+    return null;
+  };
+
+  const replayParsedBody = (proxyReq, req) => {
+    const body = serializeParsedBody(req, proxyReq);
+    if (!body) return;
+    proxyReq.setHeader('content-length', String(body.length));
+    proxyReq.write(body);
+  };
+
   const normalizeProxyTarget = (candidate) => {
     if (typeof candidate !== 'string') {
       return null;
@@ -417,7 +472,7 @@ export const registerOpenCodeProxy = (app, deps) => {
     // Dynamic target — port can change after restart
     router: () => resolveProxyTarget(),
     on: {
-      proxyReq: (proxyReq) => {
+      proxyReq: (proxyReq, req) => {
         // Inject OpenCode auth headers
         const authHeaders = getOpenCodeAuthHeaders();
         if (authHeaders.Authorization) {
@@ -427,6 +482,8 @@ export const registerOpenCodeProxy = (app, deps) => {
         // Defensive: request identity encoding from upstream OpenCode.
         // This avoids compressed-body/header mismatches in multi-proxy setups.
         proxyReq.setHeader('accept-encoding', 'identity');
+
+        replayParsedBody(proxyReq, req);
       },
       proxyRes: (proxyRes) => {
         for (const key of Object.keys(proxyRes.headers || {})) {