feat: complete session preferences and PAM fixture gates

legacy/go/tui/bg/automata.go

@@ -1,10 +1,5 @@
-// bg — cellular automata background for the TUI.
-//
-// Conway's Game of Life rendered at 30 Hz using Unicode half-block
-// characters (▀) to double the effective vertical resolution.
-// The grid is double-buffered for zero-allocation ticking, and
-// render output is built in a pre-allocated strings.Builder so the
-
+// The renderer packs two cell rows into each Unicode half-block row.
+// Two buffers let Tick update the grid without an allocation per frame.
 package bg
 
 import (
@@ -12,7 +7,6 @@ import (
 	"strings"
 )
 
-// Bright orange (accent) for alive cells, dark grey for dead.
 const (
 	fgAlive = "\x1b[38;2;255;127;0m"
 	fgDead  = "\x1b[38;2;30;30;30m"
@@ -92,8 +86,6 @@ func (a *Automata) count(g []uint8, x, y, w, h int) uint8 {
 	return c
 }
 
-// Frame returns the current generation as a single string suitable for
-// writing to the alternate screen.
 func (a *Automata) Frame() string {
 	a.buf.Reset()
 	src := a.a