feat: add responsive ultrawide work lanes

README.md

@@ -18,12 +18,13 @@ as installable binaries; building from source will remain supported.
 
 This repository is in architecture and vertical-slice phase. The installable
 binary is still a scaffold, while the isolated native UI spikes now exercise an
-interactive 3×1 workspace backed by six live comparison surfaces and the root workspace contains the first
-bounded local PTY, runtime-actor, VT engine, and capability-gated workspace
-command boundaries. The GPUI slice renders one styled actor-owned VT session in
-the primary 60% work band while five deterministic surfaces keep updating in the
-background. We are still validating selection/scrollback rendering, standalone
-runtime IPC/durability, ACP integration,
+interactive 20/60/20 workspace backed by six live comparison surfaces, and the
+root workspace contains the first bounded local PTY, runtime actor, VT engine,
+and capability-gated workspace command boundaries. The GPUI slice shows a
+responsive one-, three-, or five-lane work band—five on a 3440 px ultrawide—with
+one styled actor-owned VT session and five deterministic comparison surfaces.
+Retained-history navigation is wired. We are still validating terminal text
+selection and mouse input, standalone runtime IPC/durability, ACP integration,
 packaging, and usage-data contracts before a large implementation.
 
 ## Product shape