fix: include folder entries in deploy zip count to match server limit @W-24345651@

[WillieRuemmele]

Summary

• The Metadata API server counts all zip entries (files + folders) toward the 10,000 limit, but the CLI only counted files in its warning threshold check
• This caused the warning to undercount (Scenario A in the issue) or not fire at all (Scenario B) for folder-heavy projects like those with many LWC bundles
• Now both code paths (mdapiPath directory zip and ComponentSet converter zip) include directory entries in the count

Fixes forcedotcom/cli#3655

Work Item

@W-24345651@: Deploy zip file count doesn't match the server's: folder entries count toward the 10,000 limit

Proof of Work

• Tests: all passing (including new entryCount test)
• Lint: clean
• Type check: clean
• Build: clean

Test plan

• Deploy a project with many LWC bundles where file count < 8000 but file+folder count > 8000 — verify warning now fires
• Deploy a project where file+folder count > 10000 — verify the warning count matches the server's rejection count
• Deploy a small project — verify no spurious warnings

[soridalac]

QA notes:
Tested on: dreamhouse-lwc + generated LWC project

✅ Source deploy: zipFileCount 113 → 148 (files + directories counted)
✅ mdapi deploy: zipFileCount = 149, matches filesystem count exactly
✅ Warning fires at 8,000+ entries (tested with 2,700 LWC bundles → count 8102)
✅ Server rejects at 10,000+ entries ("Too many files in zip")
✅ Pre-built zip (--zip-file) path: no regression

[soridalac]

failed xNUTs fixed in this PR: salesforcecli/plugin-deploy-retrieve#1657