fix: populate region_shapes for flexible/single/template regions

[mpiersonsmela]

Summary

Fixes a KeyError that crashes the GUI when enabling Use Focus Map in flexible-multipoint acquisition after loading a region list.

Bug

File "control/core/scan_coordinates.py", line 614, in get_region_shape
    return self.region_shapes[region_id]
KeyError: 'R0'

Repro: switch to flexible multipoint, load a list of regions (e.g. R0..R3), check Use Focus Map → crash.

Root cause

ScanCoordinates keeps three parallel dicts keyed by region_id: region_centers, region_fov_coordinates, and region_shapes. Only add_region (well-plate) and set_manual_coordinates populate region_shapes. The other four add methods write the first two dicts but skip region_shapes:

• add_flexible_region
• add_flexible_region_with_step_size
• add_single_fov_region
• add_template_region

validate_region only checks region_centers and region_fov_coordinates, so it returns True for these regions and the subsequent self.region_shapes[region_id] lookup in get_region_shape raises KeyError. The focus-map grid generator hits this path through region_contains_coordinate → get_region_shape.

Fix

Set self.region_shapes[region_id] = "Square" in the four missing add methods. region_contains_coordinate only special-cases "Circle" (radius check); rectangular grids correctly fall through to the bounding-box test, so "Square" is the right value for these grid-based regions.

Test plan

• Reproduce the crash on master: load region list in flexible mode, enable Use Focus Map → KeyError
• Apply fix → enabling Use Focus Map works without exception
• Regression: well-plate mode and manual ROI still produce correct shape behavior (Circle/Square/Manual)

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