Pass URL parameters from path-to-regexp match into Call.parameters

Call.parameters was hardcoded to a placeholder object. Now the matched
route parameters are threaded through from the dispatcher to the handler
so handlers can access e.g. call.parameters.word.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/diachron/app.ts

@@ -61,7 +61,7 @@ const makeApp = ({routes, processTitle}: MakeAppArgs) => {
         console.log("DEBUG: trying pattern, match result =", match);
         if (match) {
             console.log("match", match);
-            const resp = await pr.handler(req);
+            const resp = await pr.handler(req, match.params);
 
             return resp;
         }

backend/diachron/routing.ts

@@ -29,6 +29,7 @@ const processRoutes=(routes:Route[]) :ProcessedRoutes => {
         
         const handler: InternalHandler = async (
             expressRequest: ExpressRequest,
+            params: Record<string, string>,
         ): Promise<Result> => {
             const method = massageMethod(expressRequest.method);
             
@@ -47,7 +48,7 @@ const processRoutes=(routes:Route[]) :ProcessedRoutes => {
                 pattern: route.path,
                 path: expressRequest.originalUrl,
                 method,
-                parameters: { one: 1, two: 2 },
+                parameters: params,
                 request: expressRequest,
                 user: auth.user,
                 session: new Session(auth.session, auth.user),

backend/diachron/types.ts

@@ -29,13 +29,13 @@ export type Call = {
     pattern: string;
     path: string;
     method: Method;
-    parameters: object;
+    parameters: Record<string, string>;
     request: ExpressRequest;
     user: User;
     session: Session;
 };
 
-export type InternalHandler = (req: ExpressRequest) => Promise<Result>;
+export type InternalHandler = (req: ExpressRequest, params: Record<string, string>) => Promise<Result>;
 
 export type Handler = (call: Call) => Promise<Result>;
 export type ProcessedRoute = {