Use local svgo.cmd wrapper binary

Switch SVG optimizer resolution from bin/svgo-cli.exe to bin/svgo.cmd.

Update unit tests to validate the new local binary path behavior.

Co-Authored-By: Abacus.AI CLI <agent@abacus.ai>

bin/svgo-client/README.txt

@@ -0,0 +1,16 @@
+SVGO Portable CLI
+=================
+
+SETUP:
+1. Download Node.js Windows ZIP (LTS)
+2. Extract into the "node" folder next to this file:
+   svgo_portable/
+     node/
+       node.exe
+
+3. Install dependencies:
+   npm install svgo
+
+USAGE:
+svgo.cmd -i file.svg
+svgo.cmd -i input.svg -o output.svg