Add test suite (63 tests) and CI workflow, fix Settings API bugs

Test suite covering all three layers:

Python backend (25 tests):
- AppController: state machine, start/stop, callbacks, settings reload
- API server: REST endpoints, config CRUD, status, devices
- Config: dot-notation get/set, persistence, nested paths
- Main headless: ready event port format validation

Svelte frontend (14 tests via Vitest):
- Backend store: exported properties/methods, port derivation, URLs
- Config store: method names (fetchConfig not loadConfig), defaults
- Transcriptions store: add/clear/plaintext
- File extension regression: ensures $state runes only in .svelte.ts

Rust sidecar (24 tests via cargo test):
- Platform/arch detection, asset name construction
- Ready event deserialization (with extra fields tolerance)
- Path construction, version read/write, old version cleanup
- Zip extraction, SidecarManager lifecycle

CI workflow (.gitea/workflows/test.yml):
- Runs on push to main and PRs
- Three parallel jobs: Python, Frontend, Rust

Also fixes three bugs found during test planning:
- Settings: /api/check-updates -> GET /api/check-update
- Settings: /api/remote/login -> /api/login
- Settings: /api/remote/register -> /api/register

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/tests/test_app_controller.py

@@ -0,0 +1,181 @@
+"""Tests for backend.app_controller.AppController."""
+
+import sys
+from datetime import datetime
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+# Ensure project root is on path
+project_root = Path(__file__).resolve().parent.parent.parent
+sys.path.insert(0, str(project_root))
+
+from backend.app_controller import AppState
+
+
+# ── basic state ─────────────────────────────────────────────────────
+
+
+def test_initial_state(controller):
+    """A freshly constructed controller should be INITIALIZING and not transcribing."""
+    assert controller.state == AppState.INITIALIZING
+    assert controller.is_transcribing is False
+
+
+# ── start / stop ────────────────────────────────────────────────────
+
+
+def test_start_transcription_without_engine(controller):
+    """Starting transcription before the engine is ready should fail gracefully."""
+    controller.transcription_engine = None
+    success, message = controller.start_transcription()
+    assert success is False
+    assert "not ready" in message.lower()
+
+
+def test_start_stop_cycle(controller):
+    """Full start -> stop cycle with a mocked engine that reports ready."""
+    engine = MagicMock()
+    engine.is_ready.return_value = True
+    engine.start_recording.return_value = True
+    controller.transcription_engine = engine
+
+    # Start
+    ok, msg = controller.start_transcription()
+    assert ok is True
+    assert controller.is_transcribing is True
+    assert controller.state == AppState.TRANSCRIBING
+
+    # Stop
+    ok, msg = controller.stop_transcription()
+    assert ok is True
+    assert controller.is_transcribing is False
+    engine.stop_recording.assert_called_once()
+
+
+def test_double_start_rejected(controller):
+    """Calling start_transcription twice should reject the second call."""
+    engine = MagicMock()
+    engine.is_ready.return_value = True
+    engine.start_recording.return_value = True
+    controller.transcription_engine = engine
+
+    controller.start_transcription()
+    success, message = controller.start_transcription()
+    assert success is False
+    assert "already" in message.lower()
+
+
+# ── transcription storage ───────────────────────────────────────────
+
+
+def test_clear_transcriptions(controller):
+    """clear_transcriptions should empty the list and return the count."""
+    from client.transcription_engine_realtime import TranscriptionResult
+
+    controller.transcriptions = [
+        TranscriptionResult(text="Hello", is_final=True, timestamp=datetime.now(), user_name="Alice"),
+        TranscriptionResult(text="World", is_final=True, timestamp=datetime.now(), user_name="Bob"),
+    ]
+    count = controller.clear_transcriptions()
+    assert count == 2
+    assert len(controller.transcriptions) == 0
+
+
+def test_get_transcriptions_text_with_timestamps(controller):
+    """get_transcriptions_text should include [HH:MM:SS] prefixes when requested."""
+    from client.transcription_engine_realtime import TranscriptionResult
+
+    ts = datetime(2025, 1, 15, 10, 30, 45)
+    controller.transcriptions = [
+        TranscriptionResult(text="Test line", is_final=True, timestamp=ts, user_name="User"),
+    ]
+
+    text = controller.get_transcriptions_text(include_timestamps=True)
+    assert "[10:30:45]" in text
+    assert "User:" in text
+    assert "Test line" in text
+
+
+# ── settings / engine reload ────────────────────────────────────────
+
+
+def test_apply_settings_triggers_reload_on_model_change(controller):
+    """Changing the transcription model should trigger an engine reload."""
+    controller.current_model_size = "base.en"
+    controller.current_device_config = "auto"
+
+    # Patch reload_engine so it doesn't actually try to spin up threads
+    controller.reload_engine = MagicMock(return_value=(True, "reloaded"))
+
+    reloaded, msg = controller.apply_settings({
+        "transcription.model": "small.en",
+    })
+
+    assert reloaded is True
+    controller.reload_engine.assert_called_once()
+
+
+def test_apply_settings_no_reload_when_same(controller):
+    """If model and device haven't changed, no reload should happen."""
+    controller.current_model_size = "base.en"
+    controller.current_device_config = "auto"
+
+    # Ensure config returns the same values
+    controller.config.set("transcription.model", "base.en")
+    controller.config.set("transcription.device", "auto")
+
+    controller.reload_engine = MagicMock(return_value=(True, "reloaded"))
+
+    reloaded, msg = controller.apply_settings({
+        "display.font_size": 20,
+    })
+
+    assert reloaded is False
+    controller.reload_engine.assert_not_called()
+
+
+# ── transcription callbacks ─────────────────────────────────────────
+
+
+def test_on_final_transcription_callback_fires(controller):
+    """_on_final_transcription should append and invoke on_transcription callback."""
+    from client.transcription_engine_realtime import TranscriptionResult
+
+    received = []
+    controller.on_transcription = lambda data: received.append(data)
+
+    controller.is_transcribing = True
+    controller._set_state(AppState.TRANSCRIBING)
+
+    result = TranscriptionResult(
+        text="Hello world",
+        is_final=True,
+        timestamp=datetime.now(),
+        user_name="Tester",
+    )
+    controller._on_final_transcription(result)
+
+    assert len(controller.transcriptions) == 1
+    assert len(received) == 1
+    assert received[0]["text"] == "Hello world"
+    assert received[0]["user_name"] == "Tester"
+    assert received[0]["is_preview"] is False
+
+
+def test_on_final_transcription_ignored_when_not_transcribing(controller):
+    """If the controller is not in transcribing state the callback should be a no-op."""
+    from client.transcription_engine_realtime import TranscriptionResult
+
+    controller.is_transcribing = False
+
+    result = TranscriptionResult(
+        text="Should be ignored",
+        is_final=True,
+        timestamp=datetime.now(),
+        user_name="Ghost",
+    )
+    controller._on_final_transcription(result)
+
+    assert len(controller.transcriptions) == 0