fix(cli): migrate setup model/provider pickers off simple_term_menu to curses

The setup provider->model sub-menu (and three sibling pickers) used
simple_term_menu.TerminalMenu, whose ESC and arrow-key handling was
unreliable across terminals — notably ESC failed to back out of the
model selection list on terminals that emit raw escape sequences (e.g.
Ghostty). The codebase already notes simple_term_menu 'conflicts with
/dev/tty' and causes 'ghost-duplication rendering', and a prior attempt
to migrate these (closed PR) confirmed the same root cause.

Route all four single-select pickers through the shared, already-hardened
curses_radiolist (which decodes raw CSI/SS3 escape sequences and handles
ESC consistently, fixed in #35776):

- auth.py _prompt_model_selection — model picker; the pricing column
  header and the unavailable-models block are passed as the radiolist
  description so they survive the curses screen clear. ESC now cancels.
- main.py _prompt_reasoning_effort_selection — reasoning-effort picker.
- main.py _model_flow_named_custom — named custom-provider model picker.
- main.py _remove_custom_provider — provider-removal picker.

simple_term_menu is no longer imported anywhere (only stale comments
referenced it; one in setup.py is corrected). The numbered-input
fallbacks are unchanged and still trigger on curses errors / non-TTY.

Tests: updated test_terminal_menu_fallbacks / test_reasoning_effort_menu
/ test_custom_provider_model_switch / test_model_provider_persistence to
drive the fallback via curses_radiolist errors instead of breaking
simple_term_menu. New test_setup_menu_curses_migration.py asserts each
picker routes through curses_radiolist, ESC cancels, and the pricing
header is preserved. Net -147/+183 (mostly the new test file; production
code shrinks by removing TerminalMenu boilerplate).

hermes_cli/main.py

@@ -4455,23 +4455,17 @@ def _remove_custom_provider(config):
     choices.append("Cancel")
 
     try:
-        from simple_term_menu import TerminalMenu
+        from hermes_cli.curses_ui import curses_radiolist
 
-        menu = TerminalMenu(
-            [f"  {c}" for c in choices],
-            cursor_index=0,
-            menu_cursor="-> ",
-            menu_cursor_style=("fg_red", "bold"),
-            menu_highlight_style=("fg_red",),
-            cycle_cursor=True,
-            clear_screen=False,
-            title="Select provider to remove:",
+        idx = curses_radiolist(
+            "Select provider to remove:",
+            list(choices),
+            selected=0,
+            cancel_returns=-1,
         )
-        idx = menu.show()
-        from hermes_cli.curses_ui import flush_stdin
-
-        flush_stdin()
         print()
+        if idx < 0:
+            idx = None
     except (ImportError, NotImplementedError, OSError, subprocess.SubprocessError):
         for i, c in enumerate(choices, 1):
             print(f"  {i}. {c}")
@@ -4538,27 +4532,19 @@ def _model_flow_named_custom(config, provider_info):
 
         print(f"Found {len(models)} model(s):\n")
         try:
-            from simple_term_menu import TerminalMenu
+            from hermes_cli.curses_ui import curses_radiolist
 
             menu_items = [
-                f"  {m} (current)" if m == saved_model else f"  {m}" for m in models
-            ] + ["  Cancel"]
-            menu = TerminalMenu(
+                f"{m} (current)" if m == saved_model else m for m in models
+            ] + ["Cancel"]
+            idx = curses_radiolist(
+                f"Select model from {name}:",
                 menu_items,
-                cursor_index=default_idx,
-                menu_cursor="-> ",
-                menu_cursor_style=("fg_green", "bold"),
-                menu_highlight_style=("fg_green",),
-                cycle_cursor=True,
-                clear_screen=False,
-                title=f"Select model from {name}:",
+                selected=default_idx,
+                cancel_returns=-1,
             )
-            idx = menu.show()
-            from hermes_cli.curses_ui import flush_stdin
-
-            flush_stdin()
             print()
-            if idx is None or idx >= len(models):
+            if idx < 0 or idx >= len(models):
                 print("Cancelled.")
                 return
             model_name = models[idx]
@@ -4735,26 +4721,18 @@ def _prompt_reasoning_effort_selection(efforts, current_effort=""):
         default_idx = 0
 
     try:
-        from simple_term_menu import TerminalMenu
+        from hermes_cli.curses_ui import curses_radiolist
 
-        choices = [f"  {_label(effort)}" for effort in ordered]
-        choices.append(f"  {disable_label}")
-        choices.append(f"  {skip_label}")
-        menu = TerminalMenu(
+        choices = [_label(effort) for effort in ordered]
+        choices.append(disable_label)
+        choices.append(skip_label)
+        idx = curses_radiolist(
+            "Select reasoning effort:",
             choices,
-            cursor_index=default_idx,
-            menu_cursor="-> ",
-            menu_cursor_style=("fg_green", "bold"),
-            menu_highlight_style=("fg_green",),
-            cycle_cursor=True,
-            clear_screen=False,
-            title="Select reasoning effort:",
+            selected=default_idx,
+            cancel_returns=-1,
         )
-        idx = menu.show()
-        from hermes_cli.curses_ui import flush_stdin
-
-        flush_stdin()
-        if idx is None:
+        if idx < 0:
             return None
         print()
         if idx < len(ordered):