feat: implement FParkan architecture foundation

Add the modular fparkan workspace, domain crates, adapters, apps, xtask policy/CI, acceptance evidence, and licensed corpus gates for the macOS-focused roadmap foundation.

crates/fparkan-platform/src/lib.rs

@@ -0,0 +1,93 @@
+#![forbid(unsafe_code)]
+//! Platform ports for clocks, input, events, windows, and graphics requests.
+
+/// Monotonic instant.
+#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub struct MonotonicInstant(pub u64);
+
+/// Monotonic clock.
+pub trait MonotonicClock {
+    /// Current instant.
+    fn now(&self) -> MonotonicInstant;
+}
+
+/// Platform event.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum PlatformEvent {
+    /// Quit requested.
+    Quit,
+}
+
+/// Platform error.
+#[derive(Debug)]
+pub enum PlatformError {
+    /// Backend failed.
+    Backend,
+}
+
+impl std::fmt::Display for PlatformError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{self:?}")
+    }
+}
+
+impl std::error::Error for PlatformError {}
+
+/// Event source.
+pub trait EventSource {
+    /// Polls events.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`PlatformError`] when the backend cannot collect events.
+    fn poll(&mut self, out: &mut Vec<PlatformEvent>) -> Result<(), PlatformError>;
+}
+
+/// Physical size.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct PhysicalSize {
+    /// Width.
+    pub width: u32,
+    /// Height.
+    pub height: u32,
+}
+
+/// Window port.
+pub trait WindowPort {
+    /// Drawable size.
+    fn drawable_size(&self) -> PhysicalSize;
+    /// Presents.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`PlatformError`] when the backend cannot present the current
+    /// frame.
+    fn present(&mut self) -> Result<(), PlatformError>;
+}
+
+/// Graphics profile.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum GraphicsProfile {
+    /// Desktop core.
+    DesktopCore,
+    /// Embedded profile.
+    Embedded,
+}
+
+/// Version.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct Version {
+    /// Major.
+    pub major: u8,
+    /// Minor.
+    pub minor: u8,
+}
+
+/// Graphics context request.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct GraphicsContextRequest {
+    /// Profile.
+    pub profile: GraphicsProfile,
+    /// Version.
+    pub version: Version,
+}