feat: add 2D physics subsystem with rapier2d

AGENTS.md

@@ -20,7 +20,7 @@ cargo run --locked -p pite-cli -- check
 
 ## Architecture (crate → role)
 
-`pite-cli` (the `pite` binary) → `pite-runtime` (window, main loop, hot reload) → `pite-core` (node tree, handles, lifecycle) + `pite-scene` (TOML load/validate/cache) + `pite-script` (embedded `pite` module) + `pite-render` (`Renderer2D` wgpu seam) + `pite-assets` (`Importer` trait, uid registry) + `pite-audio` (WAV/OGG/MP3/FLAC, silent-simulation fallback) + `pite-project` (`pite.toml`, `res://`, templates) + `pite-export` (binary + resolved content) + `pite-player` (lean run-only binary — the runtime without the editor) + `pite-editor` (egui panels, LSP client). Docs in `docs/` are authoritative per topic: `scene-format`, `scripting-api`, `assets`, `editor`, `manifest`, `export`, `lsp`.
+`pite-cli` (the `pite` binary) → `pite-runtime` (window, main loop, hot reload) → `pite-core` (node tree, handles, lifecycle) + `pite-scene` (TOML load/validate/cache) + `pite-script` (embedded `pite` module) + `pite-physics` (pure-Rust rapier2d 2D physics subsystem) + `pite-render` (`Renderer2D` wgpu seam) + `pite-assets` (`Importer` trait, uid registry) + `pite-audio` (WAV/OGG/MP3/FLAC, silent-simulation fallback) + `pite-project` (`pite.toml`, `res://`, templates) + `pite-export` (binary + resolved content) + `pite-player` (lean run-only binary — the runtime without the editor) + `pite-editor` (egui panels, LSP client). Docs in `docs/` are authoritative per topic: `scene-format`, `scripting-api`, `assets`, `editor`, `manifest`, `export`, `lsp`.
 
 ## Gotchas agents miss
 
@@ -36,4 +36,4 @@ cargo run --locked -p pite-cli -- check
 
 - Conventional commits (`feat:`/`fix:`/`docs:`/`chore:`), one focused change per commit/PR; never commit secrets, `target/`, or local paths.
 - New Rust files start with `// SPDX-License-Identifier: MIT OR Apache-2.0` (Python: `# …`); `examples/` game scripts stay header-free.
-- Pinned values bump in multi-file lockstep (12 internal path-dep pins, scene `FORMAT_VERSION`/`CACHE_VERSION`, the pyright pin in `lsp.rs` + docs + CI, `python_bundle.rs` pins) — checklist in `CONTRIBUTING.md`.
+- Pinned values bump in multi-file lockstep (13 internal path-dep pins, scene `FORMAT_VERSION`/`CACHE_VERSION`, the pyright pin in `lsp.rs` + docs + CI, `python_bundle.rs` pins) — checklist in `CONTRIBUTING.md`.

CHANGELOG.md

@@ -9,7 +9,14 @@
 - Editor code pane opens config text files (`toml`/`cfg`/`ini`/`json`/`yaml`/`yml`) for plain editing; LSP completion, hover, and diagnostics stay Python-only.
 - Editor code pane highlights Python and config text (keywords, strings, numbers, comments, `[...]` headers) in palette colors.
 - Editor menus reorganized: `Scene` (new/open/recent/save/save-as/quit, native dialogs, `Ctrl+N/O/Shift+S/Q` shortcuts), `Project`, and `Help` (repo/issues links, about, clipboard debug info); the `Run` menu is gone, transport buttons remain.
-- MacOS support (both dor editor and games) with cross-compile added. 
+- MacOS support (both dor editor and games) with cross-compile added.
+- 2D physics subsystem with Rapier2D: pure-Rust 2D physics powered by `rapier2d 0.23` in a new workspace crate `pite-physics`, running in a fixed 60 Hz simulation loop (`dt = 1/60`) and driving `_physics_process(delta)` in Python scripts.
+  - New node types: `StaticBody2D` (immobile bodies), `CharacterBody2D` (kinematic controller with `move_and_slide()`), `RigidBody2D` (dynamic forces and gravity), `Area2D` (trigger zones), and `CollisionShape2D` (`box`, `circle`, and `capsule` geometric colliders).
+  - Kinematic character controller: `move_and_slide()` computes sliding obstacle collision response against solid geometry while ignoring trigger sensors, automatically updating velocity and contact flags (`is_on_floor()`, `is_on_wall()`, `is_on_ceiling()`) relative to `up_direction`.
+  - Dynamic rigid bodies: `apply_impulse((x, y))` and `apply_force((x, y))` for simulation, with configurable `mass`, `gravity_scale`, and `lock_rotation`.
+  - Area trigger signals: `Area2D` emits engine-owned `body_entered`, `body_exited`, `area_entered`, and `area_exited` signals with node ID arguments.
+  - Spatial raycasts: `pite.raycast(from, to, mask=1)` performs line intersection queries against solid obstacles, returning intersection point, surface normal, distance, collider node, and body node.
+  - Editor visualization and inspection: `pite-editor` paints semi-transparent collision shape wireframe overlays (`box`, `circle`, `capsule`) directly in the viewport in design mode, with shape dropdowns and physics property controls in the Inspector.
 
 ## v0.2.0
 

CONTRIBUTING.md

@@ -29,7 +29,7 @@ cargo run -p pite-cli -- check
 
 The `v*` tag flow automates almost nothing — bump these by hand, every release:
 
-- `Cargo.toml`: `version` + all 12 internal `pite-*` path-dep pins (nothing enforces lockstep; `cargo publish` breaks otherwise).
+- `Cargo.toml`: `version` + all 13 internal `pite-*` path-dep pins (nothing enforces lockstep; `cargo publish` breaks otherwise).
 - `CHANGELOG.md`: move notes from `## Unreleased` to the release heading.
 - MSRV proof re-runs automatically (weekly + manual); if it goes red, fix code or raise `rust-version`.
 - Only when the toolchain changes: `python_bundle.rs` (`PINNED_PYTHON`, `PINNED_BUILD`, filenames, checksums).