fix: park cursor in composer; glitch stream frontier (0.9.26)

leaveok on chrome panes and always redraw input after side/log motion
so the caret no longer sticks on the Seat Deck version line. Live
assistant text briefly scrambles at the tip then settles to plaintext.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/tui.c

@@ -961,6 +961,102 @@ static long ms_since(const struct timespec *a) {
          (long)(now.tv_nsec - a->tv_nsec) / 1000000;
 }
 
+/* Stream frontier: trailing glyphs briefly scramble then settle to plaintext.
+ * Returns a malloc'd ANSI copy, or NULL to use the source as-is. */
+#define GLITCH_FRONT 28
+
+static unsigned glitch_mix(unsigned x) {
+  x ^= x << 13;
+  x ^= x >> 17;
+  x ^= x << 5;
+  return x;
+}
+
+static char *glitch_stream_frontier(const char *src, int spin) {
+  if (!src || !src[0])
+    return NULL;
+  size_t n = strlen(src);
+  char *out = malloc(n * 3 + 64); /* room if we swap ASCII for UTF-8 glyphs */
+  if (!out)
+    return NULL;
+  /* Collect starts of the last GLITCH_FRONT visible codepoints (skip SGR). */
+  size_t starts[GLITCH_FRONT];
+  size_t lens[GLITCH_FRONT];
+  int nv = 0;
+  size_t i = 0;
+  while (i < n) {
+    if (src[i] == '\033' && i + 1 < n && src[i + 1] == '[') {
+      size_t j = i + 2;
+      while (j < n && src[j] != 'm')
+        j++;
+      i = j < n ? j + 1 : n;
+      continue;
+    }
+    wchar_t wc;
+    size_t eaten;
+    utf8_decode(src + i, n - i, &wc, &eaten);
+    if (eaten == 0)
+      break;
+    if (wc != L'\n' && wc != L'\r') {
+      if (nv < GLITCH_FRONT) {
+        starts[nv] = i;
+        lens[nv] = eaten;
+        nv++;
+      } else {
+        memmove(starts, starts + 1, (GLITCH_FRONT - 1) * sizeof(starts[0]));
+        memmove(lens, lens + 1, (GLITCH_FRONT - 1) * sizeof(lens[0]));
+        starts[GLITCH_FRONT - 1] = i;
+        lens[GLITCH_FRONT - 1] = eaten;
+      }
+    }
+    i += eaten;
+  }
+  if (nv < 4) {
+    free(out);
+    return NULL;
+  }
+  static const char *const uni_g[] = {
+      "░", "▒", "▓", "█", "▄", "▀", "▌", "▐", "╳", "╬", "═", "║",
+      "ｱ", "ｲ", "ｳ", "ｴ", "ｵ", "ｶ", "ｷ", "ｸ", "#", "*", "+", "/"};
+  static const char *const asc_g[] = {
+      "#", "$", "%", "&", "*", "+", "=", "?", "/", "\\", "|", ":",
+      ".", ",", ";", "~", "^", "x", "o", "0", "1", "Z", "X", "/"};
+  const char *const *glyphs = g_ascii ? asc_g : uni_g;
+  const int ng = g_ascii ? (int)(sizeof(asc_g) / sizeof(asc_g[0]))
+                         : (int)(sizeof(uni_g) / sizeof(uni_g[0]));
+
+  size_t o = 0;
+  size_t cursor = 0;
+  for (int v = 0; v < nv; v++) {
+    size_t st = starts[v];
+    if (st > cursor) {
+      memcpy(out + o, src + cursor, st - cursor);
+      o += st - cursor;
+    }
+    /* Intensity: tip of stream most scrambled; older glyphs settle. */
+    int age = nv - 1 - v; /* 0 = newest */
+    unsigned h = glitch_mix((unsigned)spin * 131u + (unsigned)v * 17u +
+                            (unsigned)st);
+    int scramble = age < 10 && (int)(h % 10) < (10 - age);
+    if (scramble && age < 6) {
+      const char *g = glyphs[h % (unsigned)ng];
+      size_t gl = strlen(g);
+      memcpy(out + o, g, gl);
+      o += gl;
+    } else {
+      memcpy(out + o, src + st, lens[v]);
+      o += lens[v];
+    }
+    cursor = st + lens[v];
+  }
+  if (cursor < n) {
+    memcpy(out + o, src + cursor, n - cursor);
+    o += n - cursor;
+  }
+  out[o] = 0;
+  return out;
+}
+
 static void live_begin(tui_t *t) {
   live_end_cleanup(t);
   t->md_cap = MD_INIT;
@@ -1835,8 +1931,19 @@ static void build_display(tui_t *t, dlines_t *dl, int width) {
     block_to_lines_indented(&t->hist.items[i], width, t->details_all, dl);
   }
   g_dl_blk = -1;
-  if (t->as_live)
-    block_to_lines_indented(&t->live, width, t->details_all, dl);
+  if (t->as_live) {
+    block_t live = t->live;
+    char *glitch = NULL;
+    if (t->motion_on && t->busy) {
+      const char *src =
+          t->live.render ? t->live.render : (t->live.body ? t->live.body : "");
+      glitch = glitch_stream_frontier(src, t->spin);
+      if (glitch)
+        live.render = glitch;
+    }
+    block_to_lines_indented(&live, width, t->details_all, dl);
+    free(glitch);
+  }
 }
 
 /* Draws s at (y, x0) within maxw columns; returns the columns used. */
@@ -3279,6 +3386,15 @@ static void layout(tui_t *t) {
     if (t->side)
       wbkgdset(t->side, COLOR_PAIR(CP_SIDE));
   }
+  /* Side/status refreshes must not steal the terminal cursor from input. */
+  if (t->side)
+    leaveok(t->side, TRUE);
+  if (t->status)
+    leaveok(t->status, TRUE);
+  if (t->header)
+    leaveok(t->header, TRUE);
+  if (t->todow)
+    leaveok(t->todow, TRUE);
   scrollok(t->logw, FALSE);
   keypad(t->input, TRUE);
   wtimeout(t->input, 80);
@@ -7436,9 +7552,11 @@ int cst_tui_run(cst_agent_t *agent) {
     if (busy) {
       t.spin++;
       draw_status(&t);
-      draw_input(&t);
+      if (t.motion_on && t.as_live)
+        draw_log(&t); /* animate stream frontier glitch */
       if (t.motion_on && t.side)
         draw_side(&t);
+      draw_input(&t); /* always last — park cursor in the composer */
     }
 
     if (turn_done) {
@@ -7472,6 +7590,7 @@ int cst_tui_run(cst_agent_t *agent) {
       if (!busy && t.motion_on && t.side && !t.home) {
         t.spin++;
         draw_side(&t);
+        draw_input(&t); /* restore cursor after side refresh */
       }
       continue;
     }