test(e2e): add nightly-deploy-moddable cell + cleanup sweep

[ottovlotto]

Summary

• New nightly-deploy-moddable cell in test-nightly-publish matrix. Pre-creates a fresh paritytech/e2e-cli-moddable-<runId> public GH repo each run, pushes the frontend-only fixture into it, then runs dot deploy --moddable from that working dir. Asserts exit 0, "Deploy complete" summary, "Moddable: yes — <url>" line, and the registry has an entry for e2emoddab00.dot.
• The only cell that exercises the cold-start sequence a Summit attendee takes (gh repo create → push → dot deploy --moddable). mod.test.ts continues to cover the import half of the round-trip.
• Replaces e2e-cleanup.yml's stub with a real 7-day sweep filtered by topic e2e-test-fixture. Known limitation documented in-workflow: registry entry at e2emoddab00.dot accumulates re-publishes (one fixed domain, same owner — bounded + benign).

Closes #107.

Required before this can be green

Add the PAT value as a repo secret at https://github.com/paritytech/playground-cli/settings/secrets/actions named E2E_GH_PAT (repo + delete_repo scopes). The PAT itself is labelled "Playground CLI cold start test" on Rebecca's GitHub account. Both the moddable cell and the cleanup sweep reference this secret. Rotate before 2026-08-20 (90-day expiry).

Test plan

• Add E2E_GH_PAT secret to repo settings
• Manual dispatch of E2E Tests workflow on this branch — confirm nightly-deploy-moddable cell appears and runs
• On green: confirm paritytech/e2e-cli-moddable-<runId> exists on GitHub with e2e-test-fixture topic
• Confirm registry has an entry for e2emoddab00.dot (any dot mod e2emoddab00 should succeed after this lands)
• Manual dispatch of E2E Cleanup workflow — confirms sweep wiring without waiting a week; with a fresh moddable repo (<7 days old) it should list nothing to delete

Design decisions (locked during planning)

• Per-run fresh repo over static fixture — tests the URL-stamping against a varying URL (catches hardcode regressions) AND covers the gh create + push + deploy timing. The static-fixture alternative would miss both.
• No PoP step — SIGNER is NoStatus by design; the e2emoddab00 domain label (9-char base + 2 digits) is NoStatus-compatible so DotNS classification matches.
• Fail loudly on gh repo create errors — no retry, no auto-renaming. Auto-file-failure workflow opens an issue on the morning of (same pattern as fix(dot deploy): always install before build, surface build errors clearly #192).
• 7-day cleanup retention — tighter than spec's 14 days; surfaces cleanup-cron bugs sooner.
• No test-side finally cleanup — cron is source of truth; in-test delete could race the bulletin upload serialisation.

[github-actions]

Dev build ready — try this branch:

curl -fsSL https://raw.githubusercontent.com/paritytech/playground-cli/main/install.sh | VERSION=dev/e2e-nightly-deploy-moddable bash

[github-actions]

E2E Test Pass · ✅ PASS

Tag: e2e-ci-pr · Branch: e2e-nightly-deploy-moddable · Commit: 7a1dee3 · Run logs

Cell	Result	Time
pr-deploy-cdm	✅ PASS	2m02s
pr-mod	✅ PASS	2m02s
pr-deploy-foundry	✅ PASS	0m42s
pr-deploy-frontend	✅ PASS	3m32s
pr-init-session	✅ PASS	1m41s
pr-install	✅ PASS	0m48s
pr-preflight	✅ PASS	1m17s
${{ matrix.cell }}	⏭️ SKIP	0m00s
${{ matrix.cell }}	⏭️ SKIP	0m00s

Sentry traces: view spans for this run