Add basic login screen with form-based authentication

Adds /login route with HTML template that handles GET (show form) and
POST (authenticate). On successful login, sets session cookie and
redirects to /. Also adds framework support for redirects and cookies
in route handlers.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

express/app.ts

@@ -15,6 +15,7 @@ import {
     AuthorizationDenied,
     type Call,
     type InternalHandler,
+    isRedirect,
     type Method,
     massageMethod,
     methodParser,
@@ -25,8 +26,9 @@ import {
 
 const app = express();
 
-// Parse JSON request bodies
+// Parse request bodies
 app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
 
 services.logging.log({ source: "logging", text: ["1"] });
 const processedRoutes: { [K in Method]: ProcessedRoute[] } = {
@@ -111,8 +113,10 @@ async function handler(
     const method = await methodParser.parseAsync(req.method);
 
     const byMethod = processedRoutes[method];
+    console.log("DEBUG: req.path =", JSON.stringify(req.path), "method =", method);
     for (const [_idx, pr] of byMethod.entries()) {
-        const match = pr.matcher(req.url);
+        const match = pr.matcher(req.path);
+        console.log("DEBUG: trying pattern, match result =", match);
         if (match) {
             console.log("match", match);
             const resp = await pr.handler(req);
@@ -124,7 +128,7 @@ async function handler(
     const retval: Result = {
         code: httpCodes.clientErrors.NotFound,
         contentType: contentTypes.text.plain,
-        result: "not found",
+        result: "not found!",
     };
 
     return retval;
@@ -138,7 +142,18 @@ app.use(async (req: ExpressRequest, res: ExpressResponse) => {
 
     console.log(result);
 
-    res.status(code).send(result);
+    // Set any cookies from the result
+    if (result0.cookies) {
+        for (const cookie of result0.cookies) {
+            res.cookie(cookie.name, cookie.value, cookie.options ?? {});
+        }
+    }
+
+    if (isRedirect(result0)) {
+        res.redirect(code, result0.redirect);
+    } else {
+        res.status(code).send(result);
+    }
 });
 
 process.title = `diachron:${cli.listen.port}`;