feat(devcontainer): update image source and post-start setup

- Switches devcontainer image to a self-hosted registry for consistency
- Updates post-start command to include hdlbuild installation via pip

.devcontainer/devcontainer.json

@@ -1,6 +1,6 @@
 {
   "name": "Xilinx ISE 14.7",
-  "image": "xilinx-ise:14.7",
+  "image": "git.0xmax42.io/simdev/xilinx-ise:latest",
   "runArgs": [
     "--privileged",
     "--cap-add=SYS_ADMIN",
@@ -26,5 +26,5 @@
   "forwardPorts": [
     10000
   ],
-  "postStartCommand": "git config --global user.signingkey 87C8A5DD5C14DF55DBE1DB4199AC216D447E61C0 && git config --global gpg.format openpgp && git config --global commit.gpgsign true && git config --global tag.forceSignAnnotated true && sudo apt update && sudo apt upgrade -y"
+  "postStartCommand": "git config --global user.signingkey 87C8A5DD5C14DF55DBE1DB4199AC216D447E61C0 && git config --global gpg.format openpgp && git config --global commit.gpgsign true && git config --global tag.forceSignAnnotated true && pip install --upgrade --index-url https://git.0xmax42.io/api/packages/maxp/pypi/simple/ --extra-index-url https://pypi.org/simple/ hdlbuild"
 }