Halves are a straight 104 split: 36 left, 39 right

Labelled layouts for both halves, and the overview redrawn from the real
shapes rather than a placeholder ergo core. The 36/39 asymmetry means the two
halves are separate board designs, not one file mirrored - README and BOM
updated to match.

100 of the 104 positions now have a physical key; only Insert, PrtSc, ScrLk
and Pause need a layer.

Co-Authored-By: Claude Opus 5 <[email protected]>

README.md

@@ -11,7 +11,8 @@ Status: **design**. No boards ordered, no firmware written.
 
 | Board | Qty | Keys | Carries |
 |---|---|---|---|
-| `hardware/half` | 2 (mirrored) | TBD — layout not designed | MCU, matrix, USB-C, SBU split link |
+| `hardware/half-left`  | 1 | **36** | MCU, matrix, USB-C, SBU split link |
+| `hardware/half-right` | 1 | **39** | MCU, matrix, USB-C, SBU split link |
 | `hardware/numpad` | 1 | 25 (16 numpad + 9 nav) | MCU, matrix, 1 encoder, **CH334R hub**, 3 downstream ports |
 
 **Numpad layout is settled** — see `docs/numpad-layout.svg`, and
@@ -145,11 +146,19 @@ socket pads off. FR4 plate is just another JLC board.
 Use [perigoso/keyswitch-kicad-library](https://github.com/perigoso/keyswitch-kicad-library)
 for footprints — don't draw them.
 
-### Mirrored board files, not a reversible PCB
+### The halves are two different boards
 
-The socket footprint isn't mirror-symmetric, so a reversible board needs two
-socket footprints per key with one populated. Two mirrored layouts sharing one
-schematic and one BOM is simpler and keeps everything that mattered.
+Splitting a full 104 at the 6/T/G/B boundary gives **36 keys left, 39 right** —
+the right side inherits Backspace, Enter, both brackets, the backslash and an
+extra bottom-row key. They are therefore *not* mirrors, and the earlier plan of
+one layout flipped for both halves does not survive.
+
+Two separate designs: two schematics, two layouts, two fab setups, different
+diode and socket counts. A reversible PCB was never on the table anyway — the
+hotswap socket footprint isn't mirror-symmetric, so it would have needed two
+socket footprints per key with one populated.
+
+See `docs/half-left.svg` and `docs/half-right.svg`.
 
 ### RGB: numpad underglow only