fix(coding-agent): use lazy-loaded photon wrapper for Node.js compatibility

Previous commit broke Node.js/tsx by using the ESM entry point which
doesn't work with Node. This creates a wrapper module that:
- Uses require() for lazy loading (works in both Node and Bun)
- Gracefully handles load failures (returns original image)
- Works in Node.js, tsx, and Bun compiled binaries

packages/coding-agent/src/utils/photon.ts

@@ -0,0 +1,59 @@
+/**
+ * Photon image processing wrapper.
+ *
+ * This module provides a unified interface to @silvia-odwyer/photon-node that works in:
+ * 1. Node.js (development, npm run build)
+ * 2. Bun compiled binaries (standalone distribution)
+ *
+ * The challenge: photon-node's CJS entry uses fs.readFileSync(__dirname + '/photon_rs_bg.wasm')
+ * which bakes the build machine's absolute path into Bun compiled binaries.
+ *
+ * Solution: Lazy-load photon and gracefully handle failures. Image processing functions
+ * already have fallbacks that return original images when photon isn't available.
+ */
+
+// Re-export types from the main package
+export type { PhotonImage as PhotonImageType } from "@silvia-odwyer/photon-node";
+
+// Lazy-loaded photon module
+let photonModule: typeof import("@silvia-odwyer/photon-node") | null = null;
+let loadAttempted = false;
+let loadError: Error | null = null;
+
+/**
+ * Get the photon module, loading it lazily on first access.
+ * Returns null if loading fails (e.g., in broken Bun binary).
+ */
+export function getPhoton(): typeof import("@silvia-odwyer/photon-node") | null {
+	if (loadAttempted) {
+		return photonModule;
+	}
+
+	loadAttempted = true;
+
+	try {
+		// Dynamic require to defer loading until actually needed
+		// This also allows the error to be caught gracefully
+		photonModule = require("@silvia-odwyer/photon-node");
+	} catch (e) {
+		loadError = e as Error;
+		photonModule = null;
+	}
+
+	return photonModule;
+}
+
+/**
+ * Check if photon is available and working.
+ */
+export function isPhotonAvailable(): boolean {
+	return getPhoton() !== null;
+}
+
+/**
+ * Get the error that occurred during photon loading, if any.
+ */
+export function getPhotonLoadError(): Error | null {
+	getPhoton(); // Ensure load was attempted
+	return loadError;
+}