Phase 7: cockpit overlay generator, region extraction, and profile editor

Overlay generator (pure, tested) — RioJoy.Core/Overlay:
- FontFitter ports the legacy calc-fontsize auto-fit search (validated against a
  brute-force oracle); OverlayLayoutEngine ports create-data-layer's fit + h/v
  justification and adds per-region 90 deg CCW rotation; OverlayTemplate/Region +
  OverlayTemplateStore hold cell geometry/colour/rotation (regions.json).
- GoobieDataImporter parses the legacy .data label sheet into label rows.
- src/RioJoy.Overlay: SkiaSharp rasterizer (SkiaTextMeasurer shared with the engine
  so measured layout == drawn output; SkiaOverlayRenderer -> PNG;
  ProfileWallpaperGenerator). Verified end-to-end on the real cockpit art
  (regions.json + riojoy.png + TEST.data) by OverlayRenderIntegrationTests.
- RioJoy.Tray/WallpaperApplier applies via SystemParametersInfo; RioCoordinator
  generates+applies on profile activation (opt-in via AppConfig.OverlayTemplatePath).

Region geometry — tools/XcfRegionExtract parses riojoy.xcf (a GIMP-format binary
reader, no GIMP needed) into the 119-cell regions.json: per-layer offsets/size/
font/colour, with 90 deg CCW rotation on a-00 + b-10..b-1F. Base image riojoy.png.
NOTE: the wallpaper positions are a VGA chroma-split display artifact (6 displays),
not the cockpit's logical layout.

Mapping editor (first cut) — RioJoy.Tray/Editor/ProfileEditorForm renders the
config sheet's logical grid (SheetLayout parses the sheet CSV export). The iRIO
word is edited via ButtonBinding <-> RioMapEntry.Create (no hex bit-twiddling), with
a context-sensitive picker: keyboard keys by name (KeyCatalog VK names), joystick
Button N, hat direction, mouse/RIO-command enum names; modifiers only for keyboard.
Opened from the tray ("Edit profile..."). The sheet-grid layout is a starting point
that needs rework from a better-formatted source.

~220 xUnit tests green. Docs (PLAN.md, README) updated.

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

tests/RioJoy.Core.Tests/Editing/SheetLayoutTests.cs

@@ -0,0 +1,78 @@
+using RioJoy.Core.Editing;
+using Xunit;
+
+namespace RioJoy.Core.Tests.Editing;
+
+public class SheetLayoutTests
+{
+    [Theory]
+    [InlineData("0F", 0x0F)]
+    [InlineData("50", 0x50)]
+    [InlineData("6F", 0x6F)]
+    [InlineData("00", 0x00)]
+    public void AddressFromText_ParsesHexCells(string text, int expected)
+    {
+        Assert.Equal(expected, SheetLayout.AddressFromText(text));
+    }
+
+    [Theory]
+    [InlineData("HOME")]
+    [InlineData("RIO_0")]
+    [InlineData("70")]   // > 0x6F
+    [InlineData("M U")]
+    [InlineData("0")]    // single digit
+    public void AddressFromText_RejectsNonAddresses(string text)
+    {
+        Assert.Null(SheetLayout.AddressFromText(text));
+    }
+
+    [Theory]
+    [InlineData(0x00, SheetSection.Contacts)]
+    [InlineData(0x10, SheetSection.Secondary)]
+    [InlineData(0x18, SheetSection.Screen)]
+    [InlineData(0x2F, SheetSection.Letters)]
+    [InlineData(0x38, SheetSection.Throttle)]
+    [InlineData(0x40, SheetSection.Joystick)]
+    [InlineData(0x50, SheetSection.Keypad)]
+    [InlineData(0x6F, SheetSection.ExtKeypad)]
+    public void SectionForAddress_Classifies(int address, SheetSection expected)
+    {
+        Assert.Equal(expected, SheetLayout.SectionForAddress(address));
+    }
+
+    [Fact]
+    public void Parse_BuildsCellsWithGridPositions()
+    {
+        const string csv =
+            "\"\",\"IsLit\",\"\",\"\",\"0F\"\n" +
+            "\"\",\"\",\"\",\"\",\"HOME\"";
+
+        IReadOnlyList<SheetCell> cells = SheetLayout.Parse(csv);
+
+        SheetCell addr = Assert.Single(cells, c => c.Text == "0F");
+        Assert.Equal(0x0F, addr.Address);
+        Assert.Equal(SheetSection.Contacts, addr.Section);
+        Assert.Equal(0, addr.Row);
+        Assert.Equal(4, addr.Col);
+
+        SheetCell key = Assert.Single(cells, c => c.Text == "HOME");
+        Assert.Null(key.Address);
+        Assert.Equal(1, key.Row);
+        Assert.Equal(4, key.Col);
+    }
+
+    [Fact]
+    public void Parse_RealSheet_HasFullAddressMap()
+    {
+        IReadOnlyList<SheetCell> cells = SheetLayout.Load(
+            TestRepo.CustomBackground("config-sheet.csv"));
+
+        // Every RIO address 0x00..0x6F that exists should appear exactly once as a cell.
+        var addresses = cells.Where(c => c.Address is not null).Select(c => c.Address!.Value).ToHashSet();
+        Assert.Contains(0x00, addresses);
+        Assert.Contains(0x2F, addresses); // a letter button
+        Assert.Contains(0x50, addresses); // keypad
+        Assert.Contains(0x6F, addresses); // ext keypad
+        Assert.True(addresses.Count >= 100, $"expected most of the address map, got {addresses.Count}");
+    }
+}