feat(devcontainer): add Xilinx ISE development configuration

- Introduces a devcontainer setup for Xilinx ISE 14.7
- Configures remote user, workspace, and extensions
- Adds custom VS Code settings and post-start commands
- Improves development environment portability and consistency

.devcontainer/devcontainer.json

@@ -0,0 +1,30 @@
+{
+  "name": "Xilinx ISE 14.7",
+  "image": "git.0xmax42.io/simdev/xilinx-ise:latest",
+  "runArgs": [
+    "--privileged",
+    "--cap-add=SYS_ADMIN",
+    "--shm-size=2g",
+    "-v",
+    "/run/user/1000/gnupg/S.gpg-agent:/home/xilinx/.gnupg/S.gpg-agent"
+  ],
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "/home/xilinx/vsxirepo/vhdl-by-hgb.vsix",
+        "eamodio.gitlens"
+      ],
+      "settings": {
+        "terminal.integrated.defaultProfile.linux": "bash"
+      }
+    }
+  },
+  "remoteUser": "xilinx",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/${localWorkspaceFolderBasename},type=bind",
+  "workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
+  "features": {},
+  "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 && pip install --upgrade --index-url https://git.0xmax42.io/api/packages/maxp/pypi/simple/ --extra-index-url https://pypi.org/simple/ hdlbuild"
+}