fix(init): skip sudo as root, install git before foundry, fix cold-start log capture

[EnderOfWorlds007]

Summary

• toolchain.ts: added sudo() helper that emits "sudo " when process is not running as root and "" when it is (bare Ubuntu containers run as root without sudo installed). Applies to the IPFS install and git install steps.
• toolchain.ts: moved git install step before foundry step — foundryup-polkadot clones repos via git, so git must be present before foundry runs.
• .github/workflows/e2e.yml: rewrote the Init cold-start smoke test step so tee /tmp/cold-start.log runs on the runner host (outside docker), fixing the "No such file or directory" error. Injected sudo git into the container's apt-get preflight so the sudo() guard has sudo available on non-root systems.

Test plan

• CI: pr-install cell — runs the cold-start test against the checked-in binary
• CI: all other E2E cells (no regressions)

[github-actions]

Dev build ready — try this branch:

curl -fsSL https://raw.githubusercontent.com/paritytech/playground-cli/main/install.sh | VERSION=dev/worktree-agent-ab029d06894c6eea3 bash

[github-actions]

E2E Test Pass · ✅ PASS

Tag: e2e-ci-pr · Branch: worktree-agent-ab029d06894c6eea3 · Commit: f89b37a · Run logs

Cell	Result	Time
pr-init-session	✅ PASS	1m45s
pr-mod	✅ PASS	1m23s
pr-install	✅ PASS	0m47s
pr-deploy-foundry	✅ PASS	1m17s
pr-deploy-frontend	✅ PASS	3m34s
pr-preflight	✅ PASS	1m42s
pr-deploy-cdm	✅ PASS	2m49s
${{ matrix.cell }}	⏭️ SKIP	0m00s
${{ matrix.cell }}	⏭️ SKIP	0m00s

Sentry traces: view spans for this run