chore: add devcontainer for codespaces, use default /workspace mount for code

[plexoos]

No description provided.

[Copilot]

Pull request overview

This PR modernizes the devcontainer configuration to use GitHub Codespaces' default /workspaces mount point instead of the custom /src/eic-opticks path. The changes simplify the devcontainer setup by removing custom mount configurations and add a dedicated codespace configuration.

Key changes:

• Updates OPTICKS_HOME environment variable from /src/eic-opticks to /workspaces/eic-opticks in Dockerfile
• Removes custom workspace folder and mount configurations from main devcontainer
• Adds new codespace-specific devcontainer configuration using prebuilt base image

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Dockerfile	Updates OPTICKS_HOME path to align with standard Codespaces workspace mount location
.devcontainer/devcontainer.json	Removes custom mount and workspaceFolder settings to use Codespaces defaults
.devcontainer/codespace/devcontainer.json	Adds minimal codespace configuration using prebuilt base image

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Changing OPTICKS_HOME from /src/eic-opticks to /workspaces/eic-opticks creates inconsistencies with the GitHub Actions workflow. The workflow file .github/workflows/build-pull-request.yaml (lines 77-78) references hardcoded paths like /src/eic-opticks/tests/test_opticks.sh and /src/eic-opticks/tests/test_simg4ox.sh. Since the Dockerfile copies code to $OPTICKS_HOME and the workflow tests run against the built image, these test commands will fail because the paths no longer exist in the container.

The workflow file should be updated to use /workspaces/eic-opticks/tests/... or reference the $OPTICKS_HOME environment variable instead.

Suggested change

	ENV OPTICKS_HOME=/workspaces/eic-opticks
	ENV OPTICKS_HOME=/src/eic-opticks

[Copilot]

The codespace devcontainer references the prebuilt image ghcr.io/bnlnpps/eic-opticks:base, which was built with the old OPTICKS_HOME=/src/eic-opticks path. This creates an inconsistency because:

1. The Dockerfile now sets OPTICKS_HOME=/workspaces/eic-opticks
2. Codespaces will mount the workspace at /workspaces/eic-opticks by default
3. But the existing base image still expects code at /src/eic-opticks

This means the codespace configuration won't work correctly until the base image is rebuilt and republished with the updated Dockerfile. Consider either building the image locally in the codespace devcontainer (like the main devcontainer does), or ensuring the base image is rebuilt before this configuration is used.

Suggested change

	"image": "ghcr.io/bnlnpps/eic-opticks:base"
	"build": {
	"dockerfile": "../Dockerfile"
	}