fix: enable strict mode, honest HTTP boundary, and add routing

Three fixes to the parts of the template that contradicted its own
"illegal states unrepresentable" claim:

- tsconfig: turn on strict + strictTemplates (measured zero fallout —
  the codebase already typechecked cleanly, it just wasn't enforced).
- RemoteData<T> drops its unused error type parameter (Resource.error
  is always Error) and Failure now carries a real Error. Pages read the
  union with @let instead of re-deriving from the resource, which
  deletes the non-null assertion strictNullChecks would otherwise flag.
- users.adapter.ts never checked response.ok, so an HTTP error resolved
  as a garbage Success and crashed instead of reaching RemoteData's
  Failure branch. New shared/infrastructure/http.ts adds the status
  check plus hand-written parse guards and abortSignal forwarding; the
  six fetch stubs across the test suite (which encoded the missing
  check) and adapter spec now cover the Failure and Empty paths.

Also adds real routing (@angular/router was a dependency with zero
imports and a fake "Back" button): /users and /users/:id are now
deep-linkable via withComponentInputBinding(), tested with
RouterTestingHarness driving real navigation.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/app.ts

@@ -1,10 +1,9 @@
 import { Component } from '@angular/core';
-import { UsersPage } from '@users/ui/users.page';
+import { RouterOutlet } from '@angular/router';
 
 @Component({
   selector: 'app-root',
-  imports: [UsersPage],
+  imports: [RouterOutlet],
   templateUrl: './app.html',
-  styleUrl: './app.css',
 })
 export class App {}