refactor: extract self-contained colormaps module

[patrickoleary]

refactor: extract self-contained trame-colormaps module

Note: This pull request will fail until trame-colormaps is at PyPI it is currently at trame-colormaps

QuickView previously contained ~1,400 lines of hand-rolled colormap
state management, color transfer function algorithms, log/symlog/discrete
transforms, tick computation, and colorbar/control-panel UI spread across
view_manager.py, components/view.py, app.py, utils/color.py, and
utils/math.py.

All of that functionality is now provided by the external trame-colormaps
package (pip-installable). The integration reduces to a handful of imports
and a single widget call per view:

• ColormapController wires the VTK mapper, manages presets and range
• create_colorbar(orientation='horizontal') renders the full colorbar
  with its popup control panel

Removed colormap functionality from:

• view_manager.py (-800 lines): colormap state, controller wiring, range/preset logic
• components/view.py (-209 lines): create_bottom_bar colorbar widget
• utils/color.py (-125 lines, deleted): color transfer function helpers
• utils/math.py (-265 lines): tick computation and scale transform math
• app.py (-25 lines): colormap initialization and state serialization

Added:

• pyproject.toml: trame-colormaps>=0.1.0 dependency
• ViewConfiguration fields matching the trame-colormaps API