Initial commit: Unity Needle AR Menu project with MenuScene and SampleScene web apps

Add root .gitignore for Unity Library/Temp/Logs, IDE folders, and node_modules.
Include Assets, Needle TypeScript (MenuController, asset picker, WebXR), and project configuration.

Made-with: Cursor

.agents/skills/needle-engine/references/postprocessing.md

@@ -0,0 +1,111 @@
+# Needle Engine — Post-Processing Reference
+
+Needle Engine uses the [pmndrs postprocessing](https://github.com/pmndrs/postprocessing) library. Postprocessing loads asynchronously via `NEEDLE_ENGINE_MODULES.POSTPROCESSING` (same pattern as physics). Add and remove effects via `this.context.postprocessing`.
+
+## API (`this.context.postprocessing`)
+```ts
+import { BloomEffect } from "@needle-tools/engine";
+
+// Add/remove effects
+const bloom = new BloomEffect();
+bloom.intensity.value = 3;
+bloom.threshold.value = 0.5;
+this.context.postprocessing.addEffect(bloom);
+this.context.postprocessing.removeEffect(bloom);
+
+// Other API
+this.context.postprocessing.markDirty();             // force rebuild next frame
+this.context.postprocessing.effects;                 // readonly array of active effects
+this.context.postprocessing.multisampling = "auto";  // "auto" or number (0 to max)
+this.context.postprocessing.adaptiveResolution = true; // reduce DPR when FPS drops
+```
+
+## Built-in effects
+
+All imported from `@needle-tools/engine`. Properties use `VolumeParameter` — set values with `.value`:
+
+```ts
+// Bloom — glow on bright areas
+const bloom = new BloomEffect();
+bloom.threshold.value = 0.9;     // brightness cutoff (default: 0.9)
+bloom.intensity.value = 1;       // glow strength (default: 1)
+bloom.scatter.value = 0.7;       // spread (default: 0.7)
+
+// Depth of Field — focus blur
+import { DepthOfField, DepthOfFieldMode } from "@needle-tools/engine";
+const dof = new DepthOfField();
+dof.mode = DepthOfFieldMode.Bokeh;  // Off, Gaussian, or Bokeh
+dof.focusDistance.value = 1;         // focus distance
+dof.focalLength.value = 0.2;        // focus range
+dof.aperture.value = 20;            // bokeh scale
+
+// Vignette — darkened edges
+const vig = new Vignette();
+vig.intensity.value = 0.5;      // darkness (default: 0)
+vig.color.value = { r: 0, g: 0, b: 0, a: 1 };
+
+// Color Adjustments — exposure, contrast, hue, saturation
+const ca = new ColorAdjustments();
+ca.postExposure.value = 1;      // exposure (default: 1)
+ca.contrast.value = 0;          // -1 to 1
+ca.hueShift.value = 0;          // hue rotation
+ca.saturation.value = 0;        // saturation adjustment
+
+// Tonemapping
+const tm = new ToneMappingEffect();
+tm.setMode("AgX");              // ACES, AgX, Neutral, etc.
+tm.exposure.value = 1;
+
+// Chromatic Aberration — color fringing
+const chr = new ChromaticAberration();
+chr.intensity.value = 0.5;
+
+// Pixelation
+const pix = new PixelationEffect();
+pix.granularity.value = 10;     // pixel size
+
+// SSAO — ambient occlusion
+const ssao = new ScreenSpaceAmbientOcclusion();
+ssao.intensity.value = 2;
+ssao.samples.value = 9;         // quality vs performance
+ssao.falloff.value = 1;
+ssao.color.value = new Color(0, 0, 0);
+
+// N8AO — alternative AO (higher quality)
+import { ScreenSpaceAmbientOcclusionN8, ScreenSpaceAmbientOcclusionN8QualityMode } from "@needle-tools/engine";
+const n8ao = new ScreenSpaceAmbientOcclusionN8();
+n8ao.aoRadius.value = 1;        // world-space radius
+n8ao.intensity.value = 1;
+n8ao.quality = ScreenSpaceAmbientOcclusionN8QualityMode.Medium;
+
+// Antialiasing (SMAA)
+const aa = new Antialiasing();
+aa.preset.value = 2;            // 0=Low, 1=Medium, 2=High, 3=Ultra
+
+// Tilt Shift — miniature/diorama look
+const ts = new TiltShiftEffect();
+ts.focusArea.value = 0.4;       // in-focus band size
+ts.feather.value = 0.3;         // blur transition
+ts.offset.value = 0;            // vertical offset
+ts.rotation.value = 0;          // angle
+
+// Sharpening
+const sharp = new SharpeningEffect();
+sharp.amount = 1;               // strength (direct property, not VolumeParameter)
+sharp.radius = 1;               // radius
+```
+
+## Runtime parameter changes
+```ts
+// VolumeParameter values update the underlying shader uniforms immediately
+bloom.intensity.value = 5;  // takes effect next frame, no rebuild needed
+
+// Enable/disable individual effects
+bloom.enabled = false;       // removes from pipeline
+```
+
+## Notes
+- Post-processing is disabled during XR sessions.
+- Multisampling auto-adjusts: disabled when SMAA is present, scales down on low FPS, scales up when stable.
+- Effects are automatically ordered (Bloom before Vignette before ToneMapping, etc.). Custom effects can set `order` to control placement.
+- Alpha is preserved through the pipeline.