refactor(glyphs)!: remove legacy-kwarg shims and rename attributes

[MAfarrag]

Context

Part of the grouped render-parameter refactor (branch `refactor/grouped-render-params`, PR #274). Once the group
objects existed, the temporary backward-compat shims for the old loose keywords are no longer wanted — a clean
break plus a migration guide is preferred over long-lived shims.

Problem / Current Behaviour

Deprecation shims kept the old keywords working behind DeprecationWarnings, adding maintenance cost and
obscuring the new API.

Affected locations

File	Symbol	Notes
src/cleopatra/glyphs/gridded/array_glyph.py	_resolve_point_overlay, _resolve_frame_label, _resolve_renamed_kwarg, _pop_first	removed
src/cleopatra/styling/colorbar.py	_warn_deprecated_cbar_kwargs, _DEPRECATED_CBAR_KWARGS	removed (imported by 7 glyphs)
src/cleopatra/glyphs/gridded/array_glyph.py	ArrayGlyph.no_elem	removed (use num_domain_cells)
src/cleopatra/glyphs/gridded/array_glyph.py	text_colors	renamed to cell_value_text_colors

BREAKING CHANGE

Removed keywords now raise the ordinary TypeError (unexpected keyword argument); a bare (N, 3) array as
points raises AttributeError instead of being auto-wrapped. Loose cbar_* / ticks_spacing keys still
work (only their deprecation warning is removed). Migration steps: see the migration guide.

Proposed Solution

Delete every shim helper and the no_elem alias; give cell_value_text_colors a real default; require
PointOverlay / FrameLabel objects. _Unset/_UNSET are retained (used by the hillshade sentinel).

Out of Scope

The migration guide (separate docs issue).

Effort Estimate

Size: M
Rationale: deletions spread across 8 source modules plus test cleanup.

Definition of Done

• all shim helpers and no_elem removed
• renamed attributes have real defaults
• removed kwargs raise the natural error (no warning path)
• deprecation tests removed; functional tests unwrapped/updated
• all existing tests continue to pass