Replace RabbitMQ event publishing with Server-Sent Events

Remove the RabbitMQ-based EventPublisher trait and lapin dependency
in favor of a built-in SSE streaming endpoint. Events are now
delivered directly to clients over HTTP/TLS via a /Subscribe
endpoint, eliminating the need for an external message broker.

The server uses a tokio broadcast channel internally. The new
SseBody type implements hyper::body::Body to stream events as
JSON in SSE format. Event publishing becomes synchronous and
fire-and-forget when no subscribers are connected.

Add a subscribe command to the CLI that connects to the SSE
endpoint and prints each event as a JSON line to stdout. The
client library exposes a typed async event stream via
LdkServerClient::subscribe().

E2E tests use CliEventConsumer which spawns the CLI subscribe
command as a child process, replacing the previous raw TLS/SSE
consumer and RabbitMQ consumer.

AI tools were used in preparing this commit.

Author: joostjager

…ws/integration-tests-events-rabbitmq.yml .github/workflows/integration-tests.yml.github/workflows/integration-tests-events-rabbitmq.yml renamed to .github/workflows/integration-tests.yml .github/workflows/integration-tests-events-rabbitmq.yml renamed to .github/workflows/integration-tests.yml

@@ -10,20 +10,6 @@ jobs:
   integration-tests:
     runs-on: ubuntu-latest
 
-    services:
-      rabbitmq:
-        image: rabbitmq:3
-        env:
-          RABBITMQ_DEFAULT_USER: guest
-          RABBITMQ_DEFAULT_PASS: guest
-        ports:
-          - 5672:5672
-        options: >-
-          --health-cmd "rabbitmqctl node_health_check"
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -45,11 +31,6 @@ jobs:
       - name: Set bitcoind environment variable
         run: echo "BITCOIND_EXE=$( pwd )/bin/bitcoind-${{ runner.os }}-${{ runner.arch }}" >> "$GITHUB_ENV"
 
-      - name: Run RabbitMQ integration tests
-        run: cargo test --features integration-tests-events-rabbitmq --verbose --color=always -- --nocapture
-        env:
-          RUST_BACKTRACE: 1
-
       - name: Run end-to-end tests
         run: cargo test --manifest-path e2e-tests/Cargo.toml --verbose --color=always -- --test-threads=4 --nocapture
         env: