feat: Implement conversion service with job management and logging

- Added `ConversionService` class to handle job queuing, processing, and cancellation.
- Introduced `Job`, `JobLog`, and `JobResult` data classes to manage job details and results.
- Implemented job status tracking with enums for better state management.
- Created a web interface with HTML templates for job submission and monitoring.
- Developed CSS styles for a modern UI layout and responsive design.
- Added functionality for voice profile management in the voice mixer.
- Implemented a Docker Compose configuration for GPU support.
- Wrote unit tests for the conversion service to ensure job processing works as expected.

tests/test_service.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+import time
+from abogen.web.service import JobStatus, build_service
+
+
+def test_service_processes_job(tmp_path):
+    uploads = tmp_path / "uploads"
+    outputs = tmp_path / "outputs"
+    uploads.mkdir()
+    outputs.mkdir()
+
+    source = uploads / "sample.txt"
+    payload = "hello world"
+    source.write_text(payload, encoding="utf-8")
+
+    runner_invocations: list[str] = []
+
+    def runner(job):
+        runner_invocations.append(job.id)
+        job.add_log("processing")
+        job.progress = 1.0
+        job.processed_characters = job.total_characters or len(payload)
+        job.result.audio_path = outputs / f"{job.id}.wav"
+
+    service = build_service(
+        runner=runner,
+        output_root=outputs,
+        uploads_root=uploads,
+    )
+
+    job = service.enqueue(
+        original_filename="sample.txt",
+        stored_path=source,
+        language="a",
+        voice="af_alloy",
+        speed=1.0,
+        use_gpu=False,
+        subtitle_mode="Sentence",
+        output_format="wav",
+        save_mode="Save next to input file",
+        output_folder=outputs,
+        replace_single_newlines=False,
+        subtitle_format="srt",
+        total_characters=len(payload),
+    )
+
+    deadline = time.time() + 5
+    while time.time() < deadline and job.status not in {JobStatus.COMPLETED, JobStatus.FAILED, JobStatus.CANCELLED}:
+        time.sleep(0.05)
+
+    service.shutdown()
+
+    assert runner_invocations, "conversion runner was never called"
+    assert job.status is JobStatus.COMPLETED
+    assert job.progress == 1.0
+    assert job.result.audio_path == outputs / f"{job.id}.wav"