feat(oakplugin): wire OpenFX plugins into the node graph and renderer

- oaknode: dynamic node factory registration, PluginNode value model
  pushing PluginJobPayload, traverser texture passthrough for texture
  inputs, type-stamped RefBox::get_checked.
- oakrender: PluginExecutor dependency-inversion slot; eval resolves
  and executes plugin jobs, purple frame on failure.
- oakplugin: node_factory with full OFX param -> node input
  translation (15 types, color semantics heuristic, combo ordering,
  secret/ui_group/ui_page, clip inputs), plugin instance registry,
  render executor + duplicator installation, progress reporter and
  active-viewer provider injection points, U8/U16/F16 input
  conversion with NaN scrubbing, in-place output frame writeback fix.
- gl_bridge.rs documents the wgpu<->GL interop spike: Metal-first on
  macOS rules out wgpu-hal GL interop; offscreen GL context deferred.

End-to-end tests cover registration, param translation, CPU render
pixel assertions, identity passthrough and NaN fallback.

crates/oaknode/src/value.rs

@@ -627,6 +627,12 @@ impl NodeValueTable {
 	pub fn rows(&self) -> &[(ValueType, NodeValue, Option<String>)] {
 		&self.rows
 	}
+
+	/// Mutable row access (the render seam resolves job payloads into
+	/// finished textures in place).
+	pub fn rows_mut(&mut self) -> &mut Vec<(ValueType, NodeValue, Option<String>)> {
+		&mut self.rows
+	}
 }
 
 /// Structural equality: `Texture` compares by handle address, `Samples`