feat: mosswart client icon and Asheron's Call-inspired launcher icon

acdream had no application icon on either executable. Two marks now ship,
built from the game's own material rather than drawn freehand:

* Client - the retail mosswart head. Not an illustration of one: the actual
  creature mesh (Setup 0x02000B4F part 14, skin atlas 0x05001E11,
  ClothingBase 0x10000344) read out of client_portal.dat through acdream's
  own GfxObjMesh/SetupMesh port, then smoothed, lit and graded. Palette
  values are sampled from that texture, including the mustard belly the
  Mosswart lore calls a "foul yellow".

* Launcher - a forged ring enclosing a barbed crescent, rebuilt from
  measurements of the retail wordmark and the acclient.exe icon resource.
  An original construction in the same visual language, not a copy of the
  trademarked logo. Its warm field matches the retail client icon.

Three techniques carry the render quality, all in tools/IconForge:

* PN-triangle tessellation (smooth.py). The retail head is 104 triangles
  and renders faceted. Each triangle becomes a cubic Bezier patch built
  from its own corner positions and normals, so the silhouette genuinely
  rounds rather than merely shading smoothly - and it needs no mesh
  connectivity, which matters because UV seams would otherwise pull apart.
  Normals are welded across coincident positions first, but only within a
  crease angle, so ear fins and tusk edges stay sharp.

* Matcaps (ring.py). A Lambert rasterizer cannot produce chrome, because
  chrome is almost entirely reflection and there is nothing here to
  reflect. Sampling a lit-sphere image by the camera-space normal is the
  standard stand-in for an environment map.

* Distance-transform bevelling (chisel.py). Flat shapes become chiselled
  metal by treating distance-to-edge as height. The height field is
  blurred before differentiating; without that the medial axis of each
  stroke shows through as a hatched ridge.

Two facts worth recording, both discovered the hard way. Creature Setups
define no upright pose in PlacementFrames, so the exporter must be handed
the weenie's MotionTable id or all 17 parts stack on the origin. And a
mosswart's eyes sit on the sides of the skull like a frog's, so a dead-on
frontal turns them edge-on and the face stops reading as a mosswart at all;
the hero angle is az 266 / el 32.

Wiring: <ApplicationIcon> gives each executable its PE icon. The client's
runtime window icon is embedded rather than copied beside the binary - a
window icon has no sensible fallback if the file goes missing, and
embedding survives single-file publish. WindowIconLoaderTests guards the
resource names, which are coupled to LogicalName in the csproj by string
alone and would otherwise fail only as a silently icon-less window.

Both halves of the pipeline are deterministic and reproduce the committed
PNGs byte-for-byte, so an accidental edit shows up as a diff.

Solution builds clean; 14,378 tests pass on the standard hermetic lane
filter, 0 failures.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

assets/icons/README.md

@@ -0,0 +1,86 @@
+# acdream application icons
+
+Two marks, one family.
+
+| Mark | Files | Used by |
+|---|---|---|
+| **Client** — the mosswart head | `acdream-client-*.png`, `acdream-client.ico` | `AcDream.App` (PE icon + runtime window icon) |
+| **Launcher** — the ring and crescent | `acdream-launcher-*.png`, `acdream-launcher.ico` | `AcDream.Launcher` (PE icon + Avalonia `Window.Icon`) |
+
+Each ships PNGs at 16/24/32/48/64/128/256/512/1024 plus a multi-size `.ico`
+carrying 16 through 256.
+
+## Where the art comes from
+
+**The client mark is the retail mosswart**, not a drawing of one. It is the
+actual creature head — `Setup 0x02000B4F` part 14, skin atlas `0x05001E11`,
+`ClothingBase 0x10000344` — pulled from `client_portal.dat`, smoothed, lit and
+graded. Palette values throughout both marks are sampled from that texture:
+
+| | |
+|---|---|
+| `#ACB820` | chartreuse upper skin |
+| `#A09800` | mustard belly — the "foul yellow" the lore names |
+| `#485010` | deep olive shadow |
+| `#F2ECD2` | tusk bone |
+| `#AC7438` | ear membrane / hide |
+
+**The launcher mark is inspired by the Asheron's Call sigil** — a forged ring
+enclosing a hooked crescent — rebuilt from measurements of the retail wordmark
+and the `acclient.exe` icon resource. It is an original construction in the
+same visual language, not a copy of the logo. Its warm field matches the retail
+client icon's dark-to-gold interior.
+
+> **Note on rights.** "Asheron's Call" and its logo are trademarks of their
+> owners, and the client mark is rendered from copyrighted game art. Unlike DAT
+> content — which stays on the user's own disk — these icons are compiled into
+> the shipped binaries. If acdream is ever distributed broadly, both marks
+> should be reviewed, and the client mark is the one most likely to want an
+> original redraw using these renders as reference.
+
+## Regenerating
+
+The launcher mark is fully procedural and rebuilds anywhere:
+
+```bash
+py tools/IconForge/forge.py launcher
+```
+
+That is byte-for-byte deterministic — it reproduces the committed PNGs exactly,
+so an accidental edit is visible as a diff.
+
+The client mark renders real game geometry, so it needs the installed DATs.
+One command extracts both halves — the posed geometry and the surfaces it
+references — into `tools/IconForge/work/`:
+
+```bash
+dotnet run --project tools/MosswartArt -- 0x02000B4F 0x10000344 tools/IconForge/work/mosswart_mesh.json 0x09000009
+```
+
+The trailing MotionTable id is required. Creatures do not define an upright pose
+in `Setup.PlacementFrames`; without it every part stacks on the origin.
+
+Then:
+
+```bash
+py tools/IconForge/forge.py client
+```
+
+This is deterministic too — given the same DATs it reproduces the committed
+PNGs byte-for-byte.
+
+Requires Python with `numpy`, `pillow` and `scipy`.
+
+## How they are wired in
+
+Neither icon is loaded from disk at runtime.
+
+- **PE icon** — `<ApplicationIcon>` in each `.csproj`, pointing at the `.ico`
+  here. This is what Explorer and the taskbar shortcut show.
+- **Client window icon** — `AcDream.App.Rendering.WindowIconLoader` hands GLFW
+  four sizes at startup. The PNGs are *embedded resources* linked from this
+  directory, so there is one source of truth for the art and no missing-file
+  case at runtime. `WindowIconLoaderTests` guards the resource names, which are
+  otherwise coupled to `LogicalName` in the csproj by string only.
+- **Launcher window icon** — `AvaloniaResource` linked from here, referenced as
+  `avares://acdream-launcher/Assets/acdream-launcher.png`.