fix(browser-extension): guard project name against null textContent

[Agnik47]

Fixes #1561

Problem

createProjectSelectionModal declares its onImport callback with a non-nullable name (utils/ui-components.ts:405-411), but the call site passes Node.textContent, typed string | null:

utils/ui-components.ts(611,13): error TS2345:
Argument of type '{ id: string; name: string | null; containerTag: string; }'
is not assignable to parameter of type '{ id: string; name: string; containerTag: string; }'.

Fix

Fall back to an empty string. This matches the containerTag line directly below it and every other .textContent read in the extension — this was the only unguarded site.

selectedOption.text was considered instead (it is typed non-nullable), but rejected: per spec it strips and collapses whitespace, which would silently alter project names.

Runtime behaviour is unchanged. Options are built with option.textContent = project.name (ui-components.ts:516-518), so the value is always a string, and the disabled placeholder carries value = "", so the existing if (selectedOption.value) guard already excludes it. This is a type-safety fix only.

One correction to the issue report

The issue states the lockfile pins TypeScript 5.8.3 as a single entry that this workspace dedupes onto. That is not what the current lockfile resolves: bun install --frozen-lockfile gives apps/browser-extension its own nested typescript@5.9.3 (the root copy is 5.8.3, but the extension does not use it).

TS 5.9's DOM lib types textContent as non-nullable on Element, so check-types currently passes on main as CI would install it — the error only appears under 5.8.x, which the package's own ^5.8.3 range still permits.

So this is a latent defect rather than a red build today. Verified both ways:

	main	with this PR
TS 5.9.3 (lockfile resolution)	passes	passes
TS 5.8.3	TS2345, the package's only error	passes

Preventing recurrence

apps/browser-extension is not type-checked in CI, which is why this sat on main. This PR adds a change-gated check-types step following the existing SDK/playground detection pattern, so it runs only when apps/browser-extension changes.

Happy to drop the CI half if you'd rather keep this PR to the one-line fix.

Verification

• bun run --cwd apps/browser-extension check-types exits 0 under both TypeScript versions above; the TS2345 was the only error reported under 5.8.3
• bun test in apps/browser-extension: 12 pass, 0 fail
• biome check on the changed line is clean (the file reports a pre-existing CRLF diff on a Windows checkout only, identical before and after this change; the repo stores LF)

🤖 Generated with Claude Code

https://claude.ai/code/session_017QSriDRoFLVze1BZGrAJHV

[polylane]

Note

Production impact unlikely.

No production resources are plausibly affected by this change.

_{Polylane analysed cdb9a9c for production impact.}