feat: port Hatena server to Python 3

* Update server-side database and dynamic resource code for Python 3
* Preserve existing Flipnote, UGO, NTFT, CSS, localization, and Hatena assets
* Port Flipnote upload and movie endpoints
* Update front page UGO menu generators
* Preserve existing database and sample Flipnote data
* Add regression tests for database operations and binary formats
* Add server resource loading tests
* Maintain compatibility with the original DSi Flipnote Studio protocol

tests/test_formats.py

@@ -0,0 +1,98 @@
+from __future__ import annotations
+
+import os
+import tempfile
+import unittest
+from pathlib import Path
+
+import numpy as np
+
+from Hatenatools import NTFT, PPM, TMB, UGO
+from Hatenatools.PPM import WriteImage, get_metadata
+
+
+ROOT = Path(__file__).resolve().parents[1]
+SAMPLE_PPM = ROOT / "database" / "Creators" / "913304C0CC74CC1F" / "74CC1F_0D3AA40F2B3A0_000.ppm"
+NEWS_NTFT = ROOT / "hatenadir" / "ds" / "v2-xx" / "__ntfts" / "News.ntft"
+KAERU_NTFT = ROOT / "hatenadir" / "images" / "ds" / "kaeru.ntft"
+INDEX_UGOXML = ROOT / "hatenadir" / "ds" / "v2-xx" / "index.ugoxml"
+INBOX_UGOXML = ROOT / "hatenadir" / "ds" / "v2-xx" / "inbox.ugoxml"
+
+
+class PPMTests(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.data = SAMPLE_PPM.read_bytes()
+
+    def test_tmb_metadata_and_exact_pack(self):
+        tmb = TMB().Read(self.data[:0x6A0], DecodeThumbnail=True)
+        self.assertTrue(tmb)
+        self.assertEqual(tmb.EditorAuthorID, "913304C0CC74CC1F")
+        self.assertEqual(tmb.CurrentFilename, "74CC1F_0D3AA40F2B3A0_000.tmb")
+        self.assertEqual(tmb.FrameCount, 3)
+        self.assertEqual(tmb.GetThumbnail().shape, (64, 48))
+        self.assertEqual(tmb.Pack(), self.data[:0x6A0])
+
+    def test_ppm_full_parse_and_frame(self):
+        ppm = PPM().Read(self.data, DecodeThumbnail=True, ReadFrames=True, ReadSound=True)
+        self.assertTrue(ppm)
+        self.assertEqual(ppm.EditorAuthorID, "913304C0CC74CC1F")
+        self.assertEqual(ppm.CurrentFilename, "74CC1F_0D3AA40F2B3A0_000.ppm")
+        self.assertEqual(ppm.FrameCount, 3)
+        self.assertEqual(ppm.GetThumbnail().shape, (64, 48))
+        frame = ppm.GetFrame(0)
+        self.assertIsInstance(frame, np.ndarray)
+        self.assertEqual(frame.shape, (256, 192))
+        self.assertEqual(len(ppm.SoundData), 4)
+
+    def test_metadata_helper_infers_filetype(self):
+        ppm = PPM().Read(self.data, ReadFrames=False)
+        metadata = get_metadata(ppm)
+        self.assertEqual(metadata["Current filename"], "74CC1F_0D3AA40F2B3A0_000.ppm")
+        self.assertEqual(metadata["Number of frames"], 3)
+        self.assertIn("Frame speed", metadata)
+
+    def test_image_export(self):
+        ppm = PPM().Read(self.data, DecodeThumbnail=True, ReadFrames=False)
+        with tempfile.TemporaryDirectory() as tmp:
+            output = Path(tmp) / "thumb.png"
+            self.assertTrue(WriteImage(ppm.GetThumbnail(), str(output)))
+            self.assertGreater(output.stat().st_size, 0)
+
+
+class NTFTTests(unittest.TestCase):
+    def test_exact_roundtrip_news(self):
+        raw = NEWS_NTFT.read_bytes()
+        image = NTFT().Read(raw, (32, 32))
+        self.assertTrue(image)
+        self.assertEqual(image.Pack(), raw)
+
+    def test_exact_roundtrip_kaeru(self):
+        raw = KAERU_NTFT.read_bytes()
+        image = NTFT().Read(raw, (36, 30))
+        self.assertTrue(image)
+        self.assertEqual(image.Pack(), raw)
+
+
+class UGOTests(unittest.TestCase):
+    def _roundtrip_xml(self, path: Path):
+        ugo = UGO().ReadXML(str(path), False)
+        self.assertTrue(ugo)
+        packed = ugo.Pack()
+        self.assertIsInstance(packed, bytes)
+        self.assertEqual(packed[:4], b"UGAR")
+        decoded = UGO().Read(packed)
+        self.assertTrue(decoded)
+        # Embedded-file names are XML-side metadata and are not stored in the
+        # binary UGO format. The meaningful binary round-trip is idempotence.
+        self.assertEqual(decoded.Pack(), packed)
+
+    def test_index_xml(self):
+        self._roundtrip_xml(INDEX_UGOXML)
+
+    def test_inbox_xml(self):
+        self._roundtrip_xml(INBOX_UGOXML)
+
+
+if __name__ == "__main__":
+    unittest.main()