feat: GPUI desktop port foundation

- scene crate: full project/scene/element model, serde round-trip
  proven against the web SerializedProject shape
- transfer crate: .ocp zip container, cross-compat with web fflate
  archives proven in both directions
- storage crate: filesystem project store replacing IndexedDB,
  .ocp import/export
- media crate: ffmpeg-next 8 decoder (frames, audio, thumbnails,
  waveform summaries)
- playback crate: wall-clock anchored, frame-rounded playback clock
- gpu crate: native texture readback; compositor renders headless
  offscreen on Vulkan (spike test)
- flake devshell: rust toolchain, GPUI native deps, ffmpeg dev,
  bindgen clang args; GPUI hello-world builds
- port plan in notes/gpui-port.md

1 files changed, 165 insertions, 0 deletions

diff --git a/rust/crates/effect-defs/src/params.rs b/rust/crates/effect-defs/src/params.rs
new file mode 100644
index 00000000..cc7c43dc
--- /dev/null
+++ b/rust/crates/effect-defs/src/params.rs
@@ -0,0 +1,165 @@
+use scene::params::{ParamValue, ParamValues};
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct ParamDependency {
+    pub param: String,
+    pub equals: ParamValue,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct SelectOption {
+    pub value: String,
+    pub label: String,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct NumberParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: f64,
+    pub min: f64,
+    pub max: Option<f64>,
+    pub step: f64,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+    pub display_multiplier: Option<f64>,
+    pub unit: Option<String>,
+    pub short_label: Option<String>,
+}
+
+impl NumberParamDefinition {
+    pub fn new(
+        key: &str,
+        label: &str,
+        default_value: f64,
+        min: f64,
+        max: Option<f64>,
+        step: f64,
+    ) -> Self {
+        Self {
+            key: key.to_string(),
+            label: label.to_string(),
+            default_value,
+            min,
+            max,
+            step,
+            group: None,
+            keyframable: None,
+            dependencies: Vec::new(),
+            display_multiplier: None,
+            unit: None,
+            short_label: None,
+        }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct BooleanParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: bool,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct ColorParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: String,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct SelectParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: String,
+    pub options: Vec<SelectOption>,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct TextParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: String,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct FontParamDefinition {
+    pub key: String,
+    pub label: String,
+    pub default_value: String,
+    pub group: Option<String>,
+    pub keyframable: Option<bool>,
+    pub dependencies: Vec<ParamDependency>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum ParamDefinition {
+    Number(NumberParamDefinition),
+    Boolean(BooleanParamDefinition),
+    Color(ColorParamDefinition),
+    Select(SelectParamDefinition),
+    Text(TextParamDefinition),
+    Font(FontParamDefinition),
+}
+
+impl ParamDefinition {
+    pub fn key(&self) -> &str {
+        match self {
+            Self::Number(param) => &param.key,
+            Self::Boolean(param) => &param.key,
+            Self::Color(param) => &param.key,
+            Self::Select(param) => &param.key,
+            Self::Text(param) => &param.key,
+            Self::Font(param) => &param.key,
+        }
+    }
+
+    pub fn label(&self) -> &str {
+        match self {
+            Self::Number(param) => &param.label,
+            Self::Boolean(param) => &param.label,
+            Self::Color(param) => &param.label,
+            Self::Select(param) => &param.label,
+            Self::Text(param) => &param.label,
+            Self::Font(param) => &param.label,
+        }
+    }
+
+    pub fn default_value(&self) -> ParamValue {
+        match self {
+            Self::Number(param) => ParamValue::Number(param.default_value),
+            Self::Boolean(param) => ParamValue::Bool(param.default_value),
+            Self::Color(param) => ParamValue::String(param.default_value.clone()),
+            Self::Select(param) => ParamValue::String(param.default_value.clone()),
+            Self::Text(param) => ParamValue::String(param.default_value.clone()),
+            Self::Font(param) => ParamValue::String(param.default_value.clone()),
+        }
+    }
+
+    pub fn numeric_range(&self) -> Option<(f64, Option<f64>, f64)> {
+        match self {
+            Self::Number(param) => Some((param.min, param.max, param.step)),
+            _ => None,
+        }
+    }
+}
+
+pub fn build_default_param_values(params: &[ParamDefinition]) -> ParamValues {
+    params
+        .iter()
+        .map(|param| (param.key().to_string(), param.default_value()))
+        .collect()
+}