Match the row-budget naming introduced in PR #11260 for the approval and
clarify panels: rename chrome_reserve=14 into reserved_below=6 (input
chrome below the panel) + panel_chrome=6 (this panel's borders, blanks,
and hint row) + min_visible=3 (floor on visible items). Same arithmetic
as before, but a reviewer reading both files now sees the same handle.
Compact-chrome mode is intentionally not adopted — that pattern fits the
"fixed mandatory content might overflow" shape of approval/clarify
(solved by truncating with a marker), whereas the picker's overflow is
already handled by the scrolling viewport.
The /model picker rendered every choice into a prompt_toolkit Window
with no max height. Providers with many models (e.g. Ollama Cloud's 36+)
overflowed the terminal, clipping the bottom border and the last items.
- Add HermesCLI._compute_model_picker_viewport() to slide a scroll
offset that keeps the cursor on screen, sized from the live terminal
rows minus chrome reserved for input/status/border.
- Render only the visible slice in _get_model_picker_display() and
persist the offset on _model_picker_state across redraws.
- Bind ESC (eager) to close the picker, matching the Cancel button.
- Cover the viewport math with 8 unit tests in
tests/hermes_cli/test_model_picker_viewport.py.
