Add --all flag to preview list command

[bcotrim]

Related issues

• Fixes STU-1434

How AI was used in this PR

Claude Code (Sonnet 4.5) helped scaffold the implementation and tests based on the existing studio preview list command structure. I reviewed each change, iterated on several design decisions (flag vs. subcommand, grouping strategy, sort order, orphan coalescing), and ran the full lint/typecheck/test loop after each revision.

Proposed Changes

• Add a new --all flag to studio preview list that lists preview sites across all local Studio sites, grouped by site
• Groups are sorted by preview-site count descending, with alphabetical tie-breaking — this directly answers the "which local site is closest to the 10-preview-site limit?" question from the issue
• Orphaned snapshots (whose local site no longer exists in the config) coalesce into a single Unknown site group
• Extract a shared buildSnapshotTable() helper so the single-site and --all table rendering stay consistent
• Add 6 new tests covering the --all path (happy path, grouped headers, sort order, orphan fallback, orphan coalescing, expired badge, empty state) + 1 regression test for the single-site path

Note: The JSON output path (--format=json) is unchanged by this PR — it already dumps the full config.snapshots array regardless of the current site, so --all has no effect there. Keeping that behavior consistent with the existing command; happy to tighten it up in a follow-up if desired.

Testing Instructions

Setup: Have at least 2 local Studio sites with one or more preview sites each (use studio preview create in each site folder to generate some).

Happy path

1. npm run cli:build
2. From anywhere on disk (doesn't need to be inside a site folder): node apps/cli/dist/cli/main.mjs preview list --all
3. Verify the output shows one grouped table per local site, with a header like My Site (3 preview sites)
4. Verify groups appear in descending order of preview-site count

Regression — existing single-site behavior

1. cd into a Studio site folder
2. node apps/cli/dist/cli/main.mjs preview list
3. Verify the output is unchanged from before (single table, no grouped headers)

Edge cases

• No preview sites at all: run preview list --all with a user that has zero preview sites → friendly No preview sites found message
• Outside a site folder, no --all: run preview list from ~/Desktop or similar → clear error that the directory isn't added to Studio (unchanged behavior)
• Expired snapshots: if any preview sites are expired, verify the summary shows Found N preview sites (M expired) in the --all output
• Not logged in: run studio auth logout then preview list --all → Authentication required error (unchanged behavior)

Automated

• npm test -- apps/cli/commands/preview/tests/list.test.ts — 11 tests should pass
• npx eslint apps/cli/commands/preview/list.ts apps/cli/commands/preview/tests/list.test.ts — clean

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing 93c1089 vs trunk

app-size

Metric	trunk	93c1089	Diff	Change
App Size (Mac)	1282.41 MB	1282.41 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	93c1089	Diff	Change
load	1858 ms	1917 ms	+59 ms	🔴 3.2%

site-startup

Metric	trunk	93c1089	Diff	Change
siteCreation	8110 ms	8098 ms	12 ms	⚪ 0.0%
siteStartup	4167 ms	4289 ms	+122 ms	🔴 2.9%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[fredrikekelund]

I think we should consider excluding expired preview sites without an associated local sites. They are basically guaranteed to be deleted on the server, and they risk cluttering the output of this command.