IO-2/SHP-5/PRV-2: PSD import, SVG import + vector/text conversions, persistent disk cache

- effectcraft-psd (L1): PSD/PSB reader from Adobe's published file format spec (layers, groups,
  masks, blend modes, text engine data, lfx2 effects, fill/adjustment layers, vector masks;
  1/8/16/32-bit, RGB/CMYK/Gray/Lab/Indexed, raw/RLE/ZIP) and a minimal writer for fixtures.
- File > Import: importAs footage|composition|compositionLayerSizes, layer (Choose Layer);
  groups -> precomps (pass-through collapses), text -> editable text, styles -> Layer Styles,
  adjustments -> adjustment layers with effects; UI asks the Import Kind for Photoshop files.
- effectcraft-svg (L2): SVG parser (shapes, paths, transforms, use, CSS, gradients) and
  rasteriser; .svg imports as footage, continuously rasterised when the switch is on.
- layer.create: shapesFromVector, shapesFromText, masksFromText, editableText (stub removed).
- Disk cache (render::disk_cache): LZ4 content-keyed frames and layer buffers, LRU size limit
  from prefs, atomic writes, restart persistence; edit.purge clears it, cache.diskStats query;
  viewer frames read/write it and the timeline shows disk-only frames in blue.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/tests_disk_cache.rs

@@ -0,0 +1,121 @@
+//! The persistent disk cache (PRV-2) through the session: settings, layer cache persistence
+//! across restarts, invalidation on edits, purging.
+
+use serde_json::json;
+
+use crate::Session;
+use crate::render::RenderOpts;
+
+fn folder(name: &str) -> String {
+    let d = std::env::temp_dir().join(format!("effectcraft-session-disk-{name}-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&d);
+    d.to_string_lossy().to_string()
+}
+
+fn session(dir: &str) -> Session {
+    let mut s = Session::default();
+    s.execute_checked("prefs.set", json!({"values": {"disk.diskCacheFolder": dir, "disk.diskCacheEnabled": true}})).unwrap();
+    // Write every layer buffer, however quick to render.
+    s.disk_cache.as_ref().unwrap().set_min_layer_ms(0);
+    s
+}
+
+fn project(s: &mut Session) -> effectcraft_project::ItemId {
+    s.execute("comp.new", json!({"name": "D", "width": 160, "height": 90, "frameRate": 30, "duration": 1})).unwrap();
+    s.execute("layer.newSolid", json!({"color": "#3080ff", "width": 80, "height": 40})).unwrap();
+    s.execute("effect.apply", json!({"layer": "#1", "effect": "Gaussian Blur"})).unwrap();
+    s.execute("prop.set", json!({"layer": "#1", "path": "effects/#1/blurriness", "value": 12})).unwrap();
+    s.active_comp_id().unwrap()
+}
+
+#[test]
+fn disk_cache_settings_persistence_and_invalidation() {
+    let dir = folder("persist");
+    let mut s = session(&dir);
+    let st = s.execute_checked("cache.diskStats", json!({})).unwrap();
+    assert_eq!(st["enabled"], json!(true));
+    assert_eq!(st["maxBytes"], json!(100u64 << 30));
+    let cid = project(&mut s);
+    let t = s.time();
+    let first = s.render(cid, t, RenderOpts::default());
+    let dc = s.disk_cache.clone().unwrap();
+    dc.flush();
+    let written = dc.stats().entries;
+    assert!(written > 0, "layer buffers written");
+    // "Restart": a new session on the same folder and project renders from disk.
+    let saved = s.project.clone();
+    drop(s);
+    let mut s2 = session(&dir);
+    s2.project = saved;
+    s2.bump();
+    s2.open_comp(cid);
+    let dc2 = s2.disk_cache.clone().unwrap();
+    assert_eq!(dc2.stats().entries, written);
+    let again = s2.render(cid, t, RenderOpts::default());
+    assert!(dc2.stats().hits > 0, "{:?}", dc2.stats());
+    assert_eq!(again.data, first.data, "disk-cached pixels are exact");
+    // An edit changes the keys: a miss, and new entries.
+    let hits = dc2.stats().hits;
+    s2.execute("prop.set", json!({"layer": "#1", "path": "effects/#1/blurriness", "value": 20})).unwrap();
+    let edited = s2.render(cid, t, RenderOpts::default());
+    assert_ne!(edited.data, first.data);
+    assert_eq!(dc2.stats().hits, hits);
+    dc2.flush();
+    assert!(dc2.stats().entries > written);
+    // Purge ▸ All Disk Cache empties it; memory purge leaves the disk alone.
+    let r = s2.execute_checked("edit.purge", json!({"what": "memory"})).unwrap();
+    assert_eq!(r["diskEntries"], json!(0));
+    assert!(dc2.stats().entries > 0);
+    let r = s2.execute_checked("edit.purge", json!({"what": "disk"})).unwrap();
+    assert!(r["diskEntries"].as_u64().unwrap() > 0);
+    assert_eq!(dc2.stats().entries, 0);
+    // Disabling detaches it.
+    s2.execute_checked("prefs.set", json!({"key": "disk.diskCacheEnabled", "value": false})).unwrap();
+    assert!(s2.disk_cache.is_none());
+    assert!(s2.layer_cache.disk().is_none());
+}
+
+#[test]
+fn footage_changes_change_the_salt() {
+    let dir = folder("salt");
+    let mut s = session(&dir);
+    let foot = std::env::temp_dir().join(format!("effectcraft-salt-{}.png", std::process::id()));
+    std::fs::write(&foot, b"one").unwrap();
+    s.edit("add", None, |p, _| {
+        let f = effectcraft_project::Footage {
+            path: foot.to_string_lossy().to_string(),
+            kind: effectcraft_project::FootageKind::Still,
+            width: 1,
+            height: 1,
+            pixel_aspect: 1.0,
+            frame_rate: effectcraft_time::FrameRate::FPS_30,
+            native_rate: None,
+            duration: effectcraft_time::Tick::ZERO,
+            has_video: true,
+            has_audio: false,
+            alpha: effectcraft_project::AlphaMode::Ignore,
+            premul_color: [0.0; 3],
+            loop_count: 1,
+            codec: "PNG".into(),
+            missing: false,
+            sequence: vec![],
+            color_profile: None,
+            layer: None,
+        };
+        p.add_item("f.png", effectcraft_color::Label::Lavender, None, effectcraft_project::ItemKind::Footage(f));
+        Ok(())
+    })
+    .unwrap();
+    let a = effectcraft_render::disk_cache::footage_salt(&s.project);
+    std::fs::write(&foot, b"two, longer").unwrap();
+    let b = effectcraft_render::disk_cache::footage_salt(&s.project);
+    assert_ne!(a, b);
+    let cid = project(&mut s);
+    let k1 = effectcraft_render::disk_cache::comp_content_key(&s.project, cid);
+    s.execute("prop.set", json!({"layer": "#1", "path": "transform/opacity", "value": 50})).unwrap();
+    let k2 = effectcraft_render::disk_cache::comp_content_key(&s.project, cid);
+    assert_ne!(k1, k2);
+    // Unrelated comps do not change it.
+    s.execute("comp.new", json!({"name": "Other", "width": 10, "height": 10, "frameRate": 30, "duration": 1})).unwrap();
+    assert_eq!(effectcraft_render::disk_cache::comp_content_key(&s.project, cid), k2);
+}