fix: address shape mounting issues in StkRigAdapter

- Implement anisotropic scaling for shape mounting to prevent distortion.
- Replace bounding-box midpoint anchors with joint-based anchors for correct rotation.
- Reset node transforms to ensure clean scaling and rotation before mounting shapes.
- Introduce new helper functions for computing bounding boxes, anchors, part lengths, and scales.
- Neutralize driver rotations to maintain a consistent frame of reference during shape mounting.
- Update documentation to reflect changes and provide detailed bugfix specifications.

BUGS.md

@@ -66,3 +66,12 @@ When it is hidden it should say "Show Pose Guide"
 ### Guide visibility
 
 The guide and joints should slightly 'ghost' in front of the objects so that the use can see how well the objects are aligned to the joints and limbs.
+
+## Stickman editor (Phase 9 Round 1)
+
+> FIXED — 2026 Round 1: implemented per docs/phase9_round1_bugfix_spec.md; anisotropic scaling, joint-based anchors, and node/driver transform neutralization; verified with a 37-assertion headless smoke test.
+
+### Fix Shape Mount Math & Point Scaling in StkRigAdapter.gd
+
+Problem Summary:
+When applying .stk v1.4 data to master*rig.tscn, shapes are severely distorted:Giant Polygon Explosions (Legs): Uniformly scaling points using scale_factor = bone_length / part_length on both $X$ and $Y$ multiplies the shape's thickness, turning thin leg segments into screen-filling blocks.Misaligned Joint Rotations (Head/Torso): Using (min + max) / 2 sets the pivot to the geometric center of the shape instead of its joint connection (e.g., neck base or hip joint).Required Fixes in StkRigAdapter.gd (or ActorFactory.gd):Please refactor \_mount_shapes() / point calculation logic using the following rules:1. Anisotropic Scaling (Primary Axis Only)Do not apply scale_factor to both axes. Only scale points along the bone's primary directional axis; leave cross-axis thickness at a $1.0$ scale multiplier:Arms (Primary Axis: $X$):$$\text{point}*{\text{local}}.x = (P*x - \text{anchor}\_x) \times \left(\frac{\text{upper_arm_length}}{\text{part_length}}\right)$$$$\text{point}*{\text{local}}.y = P*y - \text{anchor}\_y$$Legs / Torso (Primary Axis: $Y$):$$\text{point}*{\text{local}}.x = P*x - \text{anchor}\_x$$$$\text{point}*{\text{local}}.y = (P*y - \text{anchor}\_y) \times \left(\frac{\text{upper_leg_length}}{\text{part_length}}\right)$$Head: Keep unscaled ($1.0$ factor) on both axes:$$\text{point}*{\text{local}} = P - \text{anchor}$$(Guard against division by zero if part_length <= 0 by defaulting the scale factor to 1.0.)2. Joint-Based Anchor Alignment (Not BBox Center)Replace bounding-box midpoint anchors with joint origins so shapes rotate correctly around the bone joints:Head Anchor: Bottom-center of bounding box (x = (min_x + max_x) / 2, y = max_y).Torso & Legs Anchor: Top-center of bounding box (x = (min_x + max_x) / 2, y = min_y).Arms Anchor: Joint-end connection (x = min_x for right arms, x = max_x for left arms, y = (min_y + max_y) / 2).3. Node Transform ResetEnsure target Body/\* container nodes have their local scale reset to Vector2(1, 1) and rotation = 0 so Godot's node hierarchy does not multiply the geometry scaling a second time.Deliverable:Please update StkRigAdapter.gd to implement these corrected coordinate transform calculations and return the full updated GDScript.