refactor(tui): /clean pass on blitz closeout — trim comments, flatten logic

- normalizeStatusBar collapses to one ternary expression
- /statusbar slash hoists the toggle value and flattens the branch tree
- shift-tab yolo comment reduced to one line
- cursorLayout/offsetFromPosition lose paragraph-length comments
- appLayout collapses the three {!overlay.agents && …} into one fragment
- StatusRule drops redundant flexShrink={0} (Yoga default)
- server.py uses a walrus + frozenset and trims the compat helper

Net -43 LoC. 237 vitest + 46 pytest green, layouts unchanged.

ui-tui/src/components/textInput.tsx

@@ -167,11 +167,8 @@ export function lineNav(s: string, p: number, dir: -1 | 1): null | number {
   return snapPos(s, Math.min(nextBreak + 1 + col, lineEnd))
 }
 
-// Cursor layout mirrors `wrap-ansi(text, cols, { wordWrap: false, hard: true })`
-// which is what `<Text wrap="wrap-char">` ends up feeding to the renderer.
-// Char-granularity wrap keeps wrap boundaries deterministic as the user
-// types — word-wrap's whitespace-preferring reshuffle causes the cursor
-// to flicker as each keystroke moves a word across a line break (blitz #9).
+// mirrors wrap-ansi(..., { wordWrap: false, hard: true }) so the declared
+// cursor lines up with what <Text wrap="wrap-char"> actually renders
 export function cursorLayout(value: string, cursor: number, cols: number) {
   const pos = Math.max(0, Math.min(cursor, value.length))
   const w = Math.max(1, cols)
@@ -205,11 +202,7 @@ export function cursorLayout(value: string, cursor: number, cols: number) {
     col += sw
   }
 
-  // The cursor renders as an inverted cell AFTER the character at `pos`
-  // (or as a standalone trailing cell when `pos === value.length`). If
-  // col has reached the wrap column, that cell overflows to the next row
-  // — match wrap-ansi's behavior so the declared cursor doesn't sit past
-  // the visual edge.
+  // trailing cursor-cell overflows to the next row at the wrap column
   if (col >= w) {
     line++
     col = 0