fix: robust terminal size detection + resize handling

- Try ioctl on stdin/stdout/stderr, then /dev/tty, then os/shutil
- Add SIGWINCH handler to re-render on terminal resize
- Clamp scroll position after resize

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

briefing

@@ -495,11 +495,36 @@ def fetch_task_content(nid):
 # ── Terminal helpers ────────────────────────────────────────────────
 
 def get_terminal_size():
+    """Get terminal rows, cols using multiple methods."""
+    # Try ioctl on multiple fds
+    for fd_try in [sys.stdout, sys.stdin, sys.stderr]:
+        try:
+            result = struct.unpack('hh', fcntl.ioctl(fd_try, termios.TIOCGWINSZ, b'\0' * 4))
+            if result[0] > 0 and result[1] > 0:
+                return result[0], result[1]
+        except Exception:
+            pass
+    # Try /dev/tty directly
     try:
-        result = struct.unpack('hh', fcntl.ioctl(sys.stdout, termios.TIOCGWINSZ, b'\0' * 4))
+        with open('/dev/tty', 'r') as tty_fd:
-        return result[0], result[1]  # rows, cols
+            result = struct.unpack('hh', fcntl.ioctl(tty_fd, termios.TIOCGWINSZ, b'\0' * 4))
+            if result[0] > 0 and result[1] > 0:
+                return result[0], result[1]
     except Exception:
-        return 40, 80
+        pass
+    # Try os/shutil
+    try:
+        sz = os.get_terminal_size()
+        return sz.lines, sz.columns
+    except Exception:
+        pass
+    try:
+        import shutil
+        sz = shutil.get_terminal_size()
+        return sz.lines, sz.columns
+    except Exception:
+        pass
+    return 40, 80
 
 
 def read_key(fd):
@@ -546,6 +571,12 @@ def tui_viewer(range_days, client):
     input_mode = False
     input_buf = ""
     status_msg = ""
+    needs_redraw = [False]  # mutable for signal handler
+
+    # Handle terminal resize
+    def on_resize(signum, frame):
+        needs_redraw[0] = True
+    signal.signal(signal.SIGWINCH, on_resize)
 
     def split_lines(content):
         return content.split('\n')
@@ -626,11 +657,17 @@ def tui_viewer(range_days, client):
         load_briefing()
 
         while True:
+            if needs_redraw[0]:
+                needs_redraw[0] = False
             render()
             key = read_key(fd)
+            if not key:
+                continue
             rows, cols = get_terminal_size()
             view_height = rows - 1
             max_scroll = max(0, len(lines) - view_height)
+            # Clamp scroll after resize
+            scroll = min(scroll, max_scroll)
 
             if input_mode:
                 if key == 'ESC':