feat: platform logos and emulator letter sections

The decoration pass now forwards the logo front matter, pointed at the
local copy. The emulators index lists every profile under the initial
the sidebar draws, so each letter link lands on its section.

tests/test_site_r2_emulators.py

@@ -172,10 +172,10 @@ class TheIndexNamesEmulatorsAndSystems(unittest.TestCase):
             "duckstation": {"emulator": "DuckStation", "core_classification": "official_port",
                             "systems": ["sony-playstation"], "files": _files(3)},
         })
-        self.assertIn("| Emulator | Systems | Files |", page)
+        self.assertIn("| Emulator | Kind | Systems | Files |", page)
+        self.assertIn("\n## D\n", page)
         self.assertNotIn("| Engine |", page)
         self.assertNotIn(" -- ", page)
-        self.assertIn("1 profile.", page)
         row = next(line for line in page.splitlines() if line.startswith("| [DuckStation]"))
         self.assertIn(f"[{siterender.system_name('sony-playstation')}]", row)
         self.assertIn("(../systems/sony.md#playstation)", row)

tests/test_site_r2_nav.py

@@ -65,9 +65,20 @@ def _present(nav: list) -> set[str]:
 # follow the labels in platforms/_guides.yml instead of a copy of them.
 from siteguides import DEVICE_GROUPS  # noqa: E402
 
+def _index_anchors(markdown: str) -> set[str]:
+    """The heading ids a generated page carries once written."""
+    _title, title_id, body = sitestarlight.split_title(markdown)
+    return sitestarlight.heading_ids(sitestarlight.pin_heading_ids(body, title_id))
+
+
 ANCHORS = {
     "platforms/index.md": {sitestarlight.toc_slug(label) for label, _ in DEVICE_GROUPS.values()},
     "systems/index.md": {"consoles-and-computers"},
+    "emulators/index.md": _index_anchors(generate_site.generate_emulators_index({
+        "duckstation": {"emulator": "DuckStation", "systems": ["sony-playstation"]},
+        "dolphin": {"emulator": "Dolphin", "systems": ["nintendo-gamecube"]},
+        "mame": {"emulator": "MAME", "systems": ["arcade"]},
+    })),
 }
 
 
@@ -109,7 +120,7 @@ class GroupsAreGroups(unittest.TestCase):
         self.assertEqual(explore["Explore/Systems"], {"href": "/retrobios/systems/", "prune": True})
         self.assertEqual(explore["Explore/Systems/Consoles and computers"]["href"],
                          "/retrobios/systems/#consoles-and-computers")
-        self.assertEqual(explore["Explore/Emulators/D"], {"href": "/retrobios/emulators/", "prune": True})
+        self.assertEqual(explore["Explore/Emulators/D"], {"href": "/retrobios/emulators/#d", "prune": True})
 
     def test_no_group_points_at_one_of_its_own_pages(self):
         """The overview a group opens on is its own index page or a section of
@@ -138,6 +149,17 @@ class EmulatorsOneLevelDeep(unittest.TestCase):
         self.assertEqual(nav, ["emulators/index.md", {"D": [
             {"Dolphin": "emulators/dolphin.md"}, {"DuckStation": "emulators/duckstation.md"}]}])
 
+    def test_every_initial_has_its_section_on_the_index(self):
+        """A letter in the sidebar lands on the section of that letter."""
+        from common import load_emulator_profiles
+
+        profiles = load_emulator_profiles(str(REPO_ROOT / "emulators"))
+        anchors = _index_anchors(generate_site.generate_emulators_index(profiles))
+        for group in generate_site._emulator_nav(profiles)[1:]:
+            (label, _pages), = group.items()
+            with self.subTest(initial=label):
+                self.assertIn(sitestarlight.toc_slug(label), anchors)
+
     def test_every_initial_holds_pages(self):
         from common import load_emulator_profiles