plasma: ESC P bitmap rows through the feedback endpoint (plasma row)

PlasmaCommands.GraphicsWrite/GraphicsRow port the display firmware graphics
command (ESC P s y x w h, MSB-left); PlasmaDisplay.RowAsync writes a locked
whole-row update; the line protocol gains `plasma row <y> <hex32>`. The
router plasma slot becomes a bounded FIFO queue: rows stream in order (a
frame must not tear), texts still coalesce to the newest, clear flushes, cap
128 with counted drops. Docs updated; 442 tests.

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

docs/FEEDBACK.md

@@ -47,6 +47,7 @@ lamp <addr> <state>       set one lamp
 lamp-all <state>          set every lamp
 plasma text [x y] <text>  write text to the plasma display
 plasma clear              clear the plasma display
+plasma row <y> <hex32>    write one full 128-px bitmap row
 ```
 
 - **`<addr>`** — RIO lamp address, decimal or `0x` hex. Valid: `0x00–0x47`
@@ -63,6 +64,15 @@ plasma clear              clear the plasma display
   (`PlasmaPosText`). To display something that starts with two numbers, quote
   it. Encoding is **Latin-1** (one byte = one char, the plasma's wire
   encoding) — do not send UTF-8 for accented characters.
+- **`plasma row`** — one full bitmap row: `<y>` 0–31 (decimal or `0x` hex),
+  then exactly **32 hex digits** = 16 bytes = 128 pixels, **MSB = leftmost**.
+  Rows are written strictly in arrival order (unlike `plasma text`, which
+  coalesces to the newest — a bitmap frame is many rows and must not tear);
+  `plasma clear` discards any queued rows/text. Up to 128 commands queue;
+  beyond that incoming rows are dropped and counted — pace full-frame pushes
+  (a 32-row frame is ~0.77 s of wire time at 9600 baud; stream changed rows,
+  as the native games did). See
+  [OUTPUT-INTEGRATION.md](OUTPUT-INTEGRATION.md#bitmap-graphics-esc-p).
 
 Malformed lines are dropped and counted (first few are logged); they **never**
 cost a client its connection. The endpoint sends no replies.
@@ -99,9 +109,10 @@ Such drops are logged once per address. `lamp-all` silently skips owned lamps.
 **Rate:** lamp commands share the 9600-baud RIO link with the ~55 ms analog
 poll, so RIOJoy coalesces per-lamp state (latest wins) and sends at most one
 *changed* lamp per 25 ms. Spam freely — identical states cost nothing — but a
-`lamp-all` sweep takes ~3 s to fully land. Plasma writes are single-flight,
-latest-pending-wins: flood-updating a score means only the newest pending text
-is written.
+`lamp-all` sweep takes ~3 s to fully land. Plasma writes are single-flight
+over a bounded queue: flooded `text` updates coalesce to the newest value,
+`clear` flushes everything queued before it, and bitmap `row`s stream in
+order.
 
 ## Rumble → lamps