feat(*): 系统渠道与画布 - 支持多规格批量调价及 Agent 入口拖动

web/src/lib/canvas/agent-launcher-position.ts

@@ -0,0 +1,38 @@
+export type AgentLauncherPosition = { right: number; bottom: number };
+export type AgentLauncherViewport = { width: number; height: number };
+export type AgentLauncherGesture = { x: number; y: number; start: AgentLauncherPosition; dragged: boolean };
+
+export const AGENT_LAUNCHER_POSITION_KEY = "canvas:agent-launcher-position:v1";
+export const AGENT_LAUNCHER_SIZE = 76;
+const MARGIN = 20; // Includes the label below the orb.
+
+export function clampAgentLauncherPosition(position: AgentLauncherPosition, viewport: AgentLauncherViewport): AgentLauncherPosition {
+    const clamp = (value: number, extent: number) => {
+        const available = Math.max(0, extent - AGENT_LAUNCHER_SIZE);
+        const margin = Math.min(MARGIN, available / 2);
+        return Math.min(Math.max(value, margin), available - margin);
+    };
+    return { right: clamp(position.right, viewport.width), bottom: clamp(position.bottom, viewport.height) };
+}
+
+export function restoreAgentLauncherPosition(raw: string | null, viewport: AgentLauncherViewport): AgentLauncherPosition {
+    if (raw) {
+        try {
+            const value = JSON.parse(raw);
+            if (value && Number.isFinite(value.right) && Number.isFinite(value.bottom)) return clampAgentLauncherPosition(value, viewport);
+        } catch {
+            // Damaged UI preferences must not hide the launcher.
+        }
+    }
+    return clampAgentLauncherPosition({ right: MARGIN, bottom: MARGIN }, viewport);
+}
+
+export function moveAgentLauncher(gesture: AgentLauncherGesture, x: number, y: number, viewport: AgentLauncherViewport) {
+    const dx = x - gesture.x;
+    const dy = y - gesture.y;
+    const dragged = gesture.dragged || Math.hypot(dx, dy) >= 6;
+    return {
+        dragged,
+        position: clampAgentLauncherPosition(dragged ? { right: gesture.start.right - dx, bottom: gesture.start.bottom - dy } : gesture.start, viewport),
+    };
+}