Fixes #618

Summary

Adds four new actions that let a binding drive a single rotation axis:

• ACTION.ROTATE_AZIMUTH / ACTION.ROTATE_POLAR (mouse)
• ACTION.TOUCH_ROTATE_AZIMUTH / ACTION.TOUCH_ROTATE_POLAR (touch)

Setting the existing ACTION.ROTATE / ACTION.TOUCH_ROTATE still enables both
axes — because they're now defined as the composite of the two new primitives:

ROTATE       = ROTATE_AZIMUTH       | ROTATE_POLAR
TOUCH_ROTATE = TOUCH_ROTATE_AZIMUTH | TOUCH_ROTATE_POLAR

Works for mouse buttons, mouse wheel, and single-finger touch.

Motivation

Previously rotation was all-or-nothing per binding; the only way to lock an axis
was to zero azimuthRotateSpeed/polarRotateSpeed globally. These actions make
axis restriction a per-binding choice (e.g. left-drag = azimuth only).

What changed

• ACTION is now composable. Each capability owns one primitive bit, and every
  existing named action is a bitwise-OR of primitives (e.g.
  TOUCH_DOLLY_ROTATE = TOUCH_DOLLY | TOUCH_ROTATE). No combined action needs its
  own dedicated bit anymore.
• Pointer/wheel dispatch tests primitive bits (state & PRIMITIVE) instead of
  exact-matching whole composites, so single-axis actions fire correctly and
  combined touch gestures decompose cleanly.
• _rotateInternal gates each axis by the rotate bits present in the current
  state (azimuth from deltaX, polar from deltaY).
• Docs + example: README and JSDoc config tables list the new constants;
  examples/config.html exposes them in every mouse/touch picker.

Bug fix (bonus)

The collapse fixes a latent bug in the drag-start handler where
TOUCH_ZOOM_SCREEN_PAN was compared against TOUCH_DOLLY_SCREEN_PAN (mismatched
constants), so two-finger zoom+screen-pan never reset target movement on drag start.

Backward compatibility

All existing ACTION member names are retained. Their numeric values
change (the enum was re-laid-out around primitives), so code that persisted raw
numeric action values rather than referencing CameraControls.ACTION.* would need
updating. Behavior of all existing bindings is unchanged.

Verification

This repo has no unit-test suite; verified via:

• npx tsc --noEmit — clean
• eslint src — clean
• npm run build — succeeds; bundle exports the new actions
• Behavioral test in examples/config.html (mouse + touch): ROTATE moves both
  axes; ROTATE_AZIMUTH moves azimuth only (polar unchanged); ROTATE_POLAR
  moves polar only (azimuth unchanged). Existing composite actions like TOUCH_DOLLY_ROTATE still work as expected