Add regression tests for prop attachment, centering, and editor UX

- Implemented test_phase9a_prop_attach.gd to validate anchor schema, alignment math, and preview isolation.
- Implemented test_phase9b_prop_centering.gd to check canonical origin presentation, bounds, centering, and save threshold.
- Implemented test_phase9c_prop_editor_ux.gd to assess the user experience in the prop editor, including anchor renaming and UI responsiveness.
- Added corresponding .uid files for each test.
- Created sync_sources.py script to manage markdown file synchronization with the notebook.
- Added .gitignore for virtual environment files.

docs/tech_debt_and_optimizations.md

@@ -45,6 +45,11 @@ This document tracks known technical debt, optimization opportunities, and minor
 | 33  | **Prop File save-serialization zeroed every point (fixed, Round 5)** — `PropFile._serialize_shape` assigned an export-format `Array` of `{x,y}` dicts directly to a typed `PackedVector2Array`; Godot's implicit conversion cannot build `Vector2` from a dictionary and silently yielded `Vector2.ZERO` per element, so every `.prop` saved by Round 1-4 wrote all points as `(0,0)` (loading as invisible/degenerate geometry). | High | ✅ Resolved | Round 5: `_serialize_shape` now routes points through `_coerce_points`; regression assertions check point *values* through `to_file_dict` and the full round-trip, plus an end-to-end canvas→save→load test. The previously saved `props/eye.prop` and `props/box.prop` are unrecoverable (coordinates were zeroed at save time) and were re-authored. Lesson: any typed `Packed*Array` assignment from dictionary/JSON data needs a Variant-coercion helper. (2026-09-19) |
 | 34  | **Prop Editor per-shape `reshaped` flag** — every shape carries `reshaped` (false by default; set by vertex insert/remove/drag and non-uniform circle scaling, cleared by `set_shape_radius`), which gates primitive-specific inspector fields (today: the circle Radius row, replaced by a muted "reshaped" note). | Low | Open | Round 6 (`specs/phase_9_prop_editor_round6.md`). Only the circle consumes the flag today; future primitive params (box W/H, plank length/thickness) should reuse it instead of adding per-type detection. An "un-reshape" affordance (restoring a clean primitive from its params) is a possible future feature. (2026-09-19) |
 | 35  | **Prop Editor selection uses a two-tone halo** — after Round 6's fill-based contrast failed for the reported "shape in front of a white shape" case (the selection extends beyond the shape onto the background), every selection element (outline polyline, bbox, rotation dot, scale crosses, vertex handles) is drawn as a dark backing pass + bright core pass. | Low | Open | Round 7 (`specs/phase_9_prop_editor_round7.md`). The pair is visible on any background but doubles the selection draw calls; negligible at sandbox scale. If a custom selection color is ever wanted (e.g. per-user theme), it should replace the core pass while keeping the halo. (2026-09-19) |
+| 36  | **Phase 9a anchor roles have no gameplay consumers yet** — `.prop` assets can author/query `grip`, `emitter`, `impact`, `mount`, and `custom`, but Phase 9a is Prop Editor-only. Secondary grips do not drive two-hand IK, and no role dispatches runtime effects, damage, mounting, or equip behavior. | Medium | Open | User-approved staging in `specs/phase_9a_prop_attach.md`: land a stable authoring/schema seam plus an isolated one-hand IK preview first. A separately approved future runtime phase must design custom-prop loading, equip/release ownership, two-hand IK, emitters, melee impacts, accessory mounting, throwing, and selector/stage persistence without assuming the editor preview is gameplay-authoritative. (2026-09-20) |
+| 37  | **Prop Editor still has no document-wide undo/redo** — Phase 9a anchor edits use the existing dirty/autosave/recovery pipeline, but there is no `UndoRedo` history for either shapes or anchors. | Medium | Open | An anchor-only stack was explicitly rejected because Arrange/Reshape edits would remain non-undoable and the UI would be inconsistent. Future work should introduce one document-level command/history boundary covering shapes, anchors, material/name changes, and preset replacement together. (2026-09-20) |
+| 38  | **Phase 9a preview does not establish runtime attachment parity** — the Prop Editor uses a private, non-physics, full-multi-shape rig preview with editor-only facing and z-order conventions. It intentionally proves anchor authoring and arm-IK evaluation, not Sandbox loading, collision, physics, mirroring, per-limb interleaving, or attachment lifecycle. | Medium | Open | A future runtime spec must independently validate the anchor transform against gameplay animation/physics and decide its visual representation, sockets or solved-wrist API, mirror strategy, collision/freeze behavior, per-limb draw order, release/ragdoll handling, and multi-shape fidelity. Do not treat preview acceptance tests as runtime tests. (2026-09-20) |
+| 39  | **Phase 9b prop centering is geometric AABB centering, not physical center of mass** — `Center Prop` uses the union AABB of internal polygon/line/circle points and deliberately excludes outline expansion, anchors, material mass, and collision geometry. | Low | Open | This is deterministic and appropriate for the fixed authoring origin, but a future physics-pivot workflow may need a separately designed center-of-mass or collision-bounds command. Phase 9b keeps canonical `origin` fixed/serialized, hides it from editing, never auto-centers after edits, and uses an explicit-save warning heuristic of `max(1024 px, 2 × bounds diagonal)`. Document-wide undo remains tracked separately by #37. (2026-09-20) |
+| 40  | **Phase 9c walking preview uses exclusive gait-or-manual ownership of the selected hand target** — the private AnimationPlayer owns the target while gait plays; beginning a cyan-target drag pauses the gait before pointer input takes ownership. | Low | Open | This deterministic policy prevents AnimationPlayer and manual IK from overwriting the same Marker2D in one frame. It means an author cannot add a live hand offset while the walk continues. If that becomes valuable, design a preview-only additive offset/blend layer rather than relying on process order. The gait remains an in-place, non-physics authoring preview and is not navigation/runtime parity (#38). (2026-09-21) |
 
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@@ -88,6 +93,9 @@ This document tracks known technical debt, optimization opportunities, and minor
 | 2026-09-11 | Phase 4c (Trigger Area Reliability) verified: `sandbox_stage.gd` `entered_area` now requires source + area instance IDs and detects visible world-AABB overlap for ANIMATED stickmen/unfrozen props, edge-triggered per area/movable pair. The prop enumeration scope bug was corrected. `tests/test_phase4c_area.gd` passed all 19 assertions, including transformed-area, leg-level overlap, wildcard/re-entry, speech consequence, stale-target, and deletion-cleanup coverage; editor verification confirmed the speech bubble fires for the configured source stickman. Logged #24 (session-only instance-ID rule references). |
 | 2026-09-12 | Phase 4.5 collision bodies verified: ten explicitly synchronized `AnimatableBody2D` proxies replace the old feet-point stickman collision poll; `PropBlock` supplies world-space contact data with shape-cast CCD; stage routing preserves rig→prop rules with per-part pair debouncing; bounded quadrant-aware flinches and PLAY→DIRECT authored-pose restoration were verified. `tests/test_phase45_collision_bodies.gd` passed 223 assertions; Phase 4b (53), Phase 4c (19), and Phase 3c (96) remained green. Reconciled #1/#5 and retained #25–#27 as intentional implementation limitations. |
 | 2026-09-17 | Phase 6a (Airborne Momentum, Procedural Air Pose, and Landing Absorption) implemented and user-verified. `StickmanRig` now carries signed ledge momentum with tuned exponential drag (`AIR_DRAG_X = 0.75`), swept horizontal proxy collision, additive free-fall pose with forward-before-lift arms, and height-driven landing absorption: falls below 80 px are soft; 80..900 px maps to 32..160 px torso compression and 270..520 px hand drop over 0.30 s. Independent foot contacts preserve ramps/stairs, while `LANDING_IMPACT` blocks primary queue progression and direct ragdoll remains an immediate preemption. `tests/test_phase6a_airborne_landing.gd` passed 24 assertions; `tests/test_phase4b_terrain.gd` passed 8 assertions. Logged #28 (per-proxy airborne sweep scaling). |
+| 2026-09-20 | Phase 9a Prop Attach specification written and refined (`specs/phase_9a_prop_attach.md`). Approved architecture: append Attach to the existing Arrange/Reshape system; additive role-based `.prop` anchors with a fixed synthesized `origin`; and an isolated Prop Editor stickman preview that uses real arm IK while showing the full authored prop. All Sandbox/custom-prop loading, attachment, sockets, physics/collision, lifecycle, and runtime tests are explicitly deferred. Logged #36 (all gameplay consumers deferred), #37 (document-wide undo remains absent), and #38 (editor preview is not a runtime-parity guarantee). Existing #29 remains open independently because the current runtime still flattens multi-shape props. |
+| 2026-09-20 | Phase 9b Prop Centering specification written (`specs/phase_9b_prop_centering.md`). Approved architecture: hide canonical origin from editable anchors while retaining it in `.prop` v1.0; draw a passive constant-screen-size `(0,0)` marker in all three modes; add an always-visible Center Prop document transaction; center the authoring camera on origin for startup/New/load/reset and preserve zoom after centering; and warn explicit saves with Center & Save / Save Anyway / Cancel when displacement exceeds `max(1024 px, 2 × bounds diagonal)`. Autosave stays silent and automatic recenter-on-edit is explicitly rejected. Logged #39 (AABB authoring center is not a future physics center of mass); #37 continues to track document-wide undo. |
+| 2026-09-21 | Phase 9c Prop Editor UX specification written (`specs/phase_9c_prop_editor_ux.md`). Approved architecture: a single Front Pose / Walk Left / Walk Right preview-motion selector with dynamic Pause/Resume; manual arm IK pauses gait before taking target ownership; modal typed anchor rename; Show Other Markers controls origin plus unselected anchors; one global Snap source; theme-driven `#262C39` inspector; container-driven unclipped chrome; simplified full-figure preview with no blue border. The preview directly plays the proven in-place gait/mirror policy and remains isolated from navigation, physics, actions, and Sandbox state. Logged #40 (exclusive gait/manual hand-target ownership). |
 
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