Sandboxes now detect and install dependencies automatically at exec time. No manual pip install or npm install needed.

What's new:

• Python: detects pyproject.toml, requirements.txt, or scans imports automatically via pipreqs

• Node: detects package.json and runs npm install

• Go: detects go.mod or initialises a new module automatically

• Java: supports Maven (pom.xml), Gradle (build.gradle), or falls back to javac

Dependencies are installed into the sandbox workspace and persist across runs. First exec is slower. Subsequent execs are fast.