Import existing LinTunes project

Snapshot of the existing codebase before working through the TASKS.md
backlog. Real library data (data/) and the iTunes import fixture
(itunes-test-library/) are gitignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

setup.py

@@ -0,0 +1,22 @@
+from setuptools import setup, find_packages
+
+setup(
+    name="lintunes",
+    version="0.1.0",
+    packages=find_packages(),
+    install_requires=[
+        "PyQt6>=6.8.0",  # QAudioBufferOutput (visualizer) needs Qt 6.8+
+        "mutagen>=1.46",
+        "numpy>=1.24",
+        "requests>=2.28",
+    ],
+    data_files=[
+        ("share/applications", ["packaging/lintunes.desktop"]),
+    ],
+    entry_points={
+        "console_scripts": [
+            "lintunes=lintunes.main:main",
+        ],
+    },
+    python_requires=">=3.9",
+)