feat(oakplugin): GL render bridge, color picker, push-button action, worker progress, Interact host

- gl_bridge: macOS CGL offscreen context (process-wide singleton,
  serialized GlGuard), real GL output textures/FBOs, glReadPixels
  readback with vertical flip and format conversion; use_opengl now
  really engages for OpenGLRenderSupported plugins (verified with real
  GL rendering: C smoke 11/11, unit tests, GL e2e).
- OfxColor: color params get a swatch button plus a real picker popup
  (RGBA sliders, live preview, hex input, undoable commit) replacing
  the four spinboxes.
- Push buttons route kOfxActionInstanceChanged (UserEdited) per the
  OFX contract; test plugin asserts the callback.
- Worker-side plugin progress flows to the main-process progress
  dialog over the NDJSON control channel, with cancel propagation.
- OFX Interact host: NewInteract/Describe lifecycle, Draw/Pen/Key/Idle
  action surface with proper in-args, DrawSuite v1 host implementation
  sharing the gl_bridge context; interact test plugin verifies the
  event stream and real GL drawing.

crates/oakplugin/tests/push_button_test.rs

@@ -0,0 +1,79 @@
+// Oak Video Editor - Non-Linear Video Editor
+// Copyright (C) 2026 Oak Team
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+//! push button → `kOfxActionInstanceChanged` 路由（端到端）。
+//!
+//! 链路：`scan_path`（最小测试插件，cbits/oak_test_plugin.c，describe
+//! 里定义了 push button 参数 "button"，instanceChanged 时按
+//! `OAK_TEST_PLUGIN_INSTANCECHANGED_MARKER` 指向的文件追加一行）→
+//! `create_instance` → `push_button_clicked`（置值 + 路由
+//! UserEdited instanceChanged）→ 插件记录回调次数。
+//!
+//! 测试插件未构建时 skip（common 约定）。宿主单例经 `common::with_host`
+//! 串行化。
+
+mod common;
+
+use oakplugin::host::Host;
+
+const PLUGIN_ID: &str = "org.oak.test-plugin";
+
+#[test]
+fn push_button_press_routes_instance_changed() {
+	common::with_host(|| {
+		let Some(dir) = common::test_plugin_scan_dir() else {
+			common::skip("最小测试插件未构建");
+			return;
+		};
+		if Host::global().cache.scan_path(&dir).is_err() {
+			common::skip("测试插件扫描失败");
+			return;
+		}
+		let inst = Host::global()
+			.create_instance(PLUGIN_ID, None)
+			.expect("实例");
+		let id = oakplugin::node_factory::register_instance(inst.clone());
+
+		// The C plugin appends one line per instanceChanged("button") to the
+		// marker file; the assertion reads it back.
+		let marker = std::env::temp_dir().join(format!("oak-push-{}.log", std::process::id()));
+		let _ = std::fs::remove_file(&marker);
+		std::env::set_var("OAK_TEST_PLUGIN_INSTANCECHANGED_MARKER", &marker);
+
+		// The button param exists and is a push button.
+		let p = inst.value.params.find("button").expect("button 参数");
+		assert_eq!(p.def.ofx_type, oakplugin::param::TYPE_PUSHBUTTON);
+
+		// First press: set + routed to the plugin.
+		assert!(oakplugin::node_factory::push_button_clicked(id, "button"));
+		// Unknown / non-button params are rejected without touching the entry.
+		assert!(!oakplugin::node_factory::push_button_clicked(id, "gain"));
+		assert!(!oakplugin::node_factory::push_button_clicked(id, "nope"));
+		assert!(!oakplugin::node_factory::push_button_clicked(u64::MAX, "button"));
+		// Second press on the real button: routed again.
+		assert!(oakplugin::node_factory::push_button_clicked(id, "button"));
+
+		// Exactly the two real presses reached the plugin's instanceChanged.
+		let log = std::fs::read_to_string(&marker).expect("marker 文件应存在");
+		assert_eq!(log.lines().count(), 2, "marker log:\n{log}");
+		assert!(log.contains("instanceChanged"), "marker log:\n{log}");
+
+		std::env::remove_var("OAK_TEST_PLUGIN_INSTANCECHANGED_MARKER");
+		let _ = std::fs::remove_file(&marker);
+		oakplugin::node_factory::unregister_instance(id);
+		Host::global().shutdown();
+	});
+}