Modernize Deno implementation and prepare for JSR

Updates everything to be compatible with Deno v2 and prepares for
publishing the packages to the [JSR](https://jsr.io) instead of
the HTTPS based imports common before the JSR.

The JSR doesn't allow for complex inferred types.[^1]
Therefore, prior `z.infer<Schema>` types have been replaced with
explicit interfaces.

Instead of the pattern of having all dependencies defined in a `deps.ts`,
it is now common practice (and requirement for the JSR) to have a `deno.json`,
which acts in a similar way to the `package.json` in NodeJS. It also serves
as an import map for dependencies, pinning their versions.

Note that while it's possible to omit the `jsr:@scope/package` and just write
`@scope/package` with this, to keep samples copy-pasteable without having to
copy the import map, imports in the samples still use the "fully qualified"
import, even though the respective versions are then pinned down using the
`deno.json` file.

In the `Dockerfile`s for the samples as well as the `docker-compose.yml` for
development in the root `backend-deno` folder, the Deno base image was upgraded
to Deno v2.

The new NATS version doesn't use (or provide) the codec functions anymore.[^2]
Therefore, the version upgrade also means that we no longer provide these as
re-exported functions.

Now, any publishing method also allows to pass a `string`, meaning one can just
use something like:

```ts
nc.publish(JSON.stringify({}));
```

Also, the `Msg` interface (any message received by NATS) now offers convenience
methods for retrieving the payload as either `json()` or a `string()`.

- JetStream is no longer included and has to be installed as `jsr:@nats-io/jetstream`;
- KV (a key-value-storage) is no longer included, but available as `jsr:@nats-io/kv`.

See <https://github.com/nats-io/nats.js/blob/e8520523a9b5316f436c44ef05ba2e50c4f6e60a/migration.md>
for a full list of changes / migration guide.

In `ensureMinimalConfig()` (which gets called by `startService()`), the function
now throws an error instead of just printing it to the console and running
`Deno.exit(1)`. This fixes various tests that failed with the upgraded Deno version.

Note that I was unable to find the change that introduced the inabilities of tests to
handle `Deno.exit(1)`. I just know that it worked previously, didn't anymore, and will
now, with this change, work once again.

[^1]: Cf. <https://jsr.io/docs/about-slow-types>
[^2]: Cf. <https://github.com/nats-io/nats.js/blob/e8520523a9b5316f436c44ef05ba2e50c4f6e60a/migration.md#changes-in-nats-base-client>

backend-deno/README.md

@@ -8,7 +8,7 @@ This library provides a framework for building Telestion services in Deno.
 ## Usage
 
 ```typescript
-import {startService} from 'https://deno.land/x/telestion/mod.ts';
+import {startService} from 'jsr:@wuespace/telestion';
 
 const {nc} = await startService();
 ```

backend-deno/cucumber/step-registry.ts

@@ -1,4 +1,4 @@
-import { resolve } from "./deps.ts";
+import { resolve } from "@std/path";
 
 /**
  * A step definition

backend-deno/cucumber/steps/config.ts

@@ -1,6 +1,6 @@
-import { startService } from "../../mod.ts";
+import { startService } from "jsr:@wuespace/telestion";
 import { Given, Then } from "../step-registry.ts";
-import { assertEquals } from "./deps.ts";
+import { assertEquals } from "@std/assert";
 
 Given('I have an environment variable named {string} with value {string}', (_ctx, key, value) => {
   Deno.env.set(key, value);

backend-deno/cucumber/steps/nats.ts

@@ -1,5 +1,6 @@
+import type { ConnectionOptions, NatsConnection } from "@nats-io/nats-core";
 import { Given, Then } from "../step-registry.ts";
-import { ConnectionOptions, NatsConnection, assert, assertEquals } from "./deps.ts";
+import { assert, assertEquals } from "@std/assert";
 
 /**
  * A mock NATS client that can be used to test services that use NATS.

backend-deno/cucumber/steps/start.ts

@@ -1,6 +1,6 @@
-import { startService } from "../../mod.ts";
+import { startService } from "jsr:@wuespace/telestion";
 import { Then, When } from "../step-registry.ts";
-import { assert, assertRejects } from "./deps.ts";
+import { assert, assertRejects } from "@std/assert";
 
 When("I start the service", async (ctx) => {
   if (!ctx.nats) {

backend-deno/cucumber/test.ts

@@ -13,8 +13,10 @@
   * MIT License (MIT)
   */
 
-import { AssertionError, parseArgs, resolve } from "./deps.ts";
+import { parseArgs } from "@std/cli";
 import { getStep, importStepDefinitions } from "./step-registry.ts";
+import { resolve } from "@std/path";
+import { AssertionError } from "@std/assert";
 
 /// Determine steps and features folder from command line arguments
 

backend-deno/deno.json

@@ -0,0 +1,23 @@
+{
+  "name": "@wuespace/telestion",
+  "license": "MIT",
+  "version": "1.0.0-alpha.4",
+  "exports": "./mod.ts",
+  "publish": {
+    "include": [
+      "mod.ts",
+      "README.md",
+      "LICENSE"
+    ]
+  },
+  "imports": {
+    "@nats-io/nats-core": "jsr:@nats-io/[email protected]",
+    "@nats-io/transport-deno": "jsr:@nats-io/[email protected]",
+    "@std/assert": "jsr:@std/assert@^1.0.8",
+    "@std/cli": "jsr:@std/cli@^1.0.7",
+    "@std/jsonc": "jsr:@std/jsonc@^1.0.1",
+    "@std/path": "jsr:@std/path@^1.0.8",
+    "jsr:@wuespace/telestion": "./mod.ts",
+    "zod": "npm:zod@^3.23.8"
+  }
+}

backend-deno/docker-compose.yml

@@ -1,7 +1,8 @@
 services:
   backend-deno:
-    image: denoland/deno:1.39.0
-    command: [ "test", "--allow-all", "/app/cucumber/test.ts", "--",
+    image: denoland/deno:2.1.2
+    working_dir: /app
+    command: [ "test", "--allow-all", "./cucumber/test.ts", "--",
                "--features", "/features",
                "--steps", "/app/cucumber/steps", ]
     volumes: