Fix company dashboard greeting fallback

[eutv2022]

Closes #70.

This prevents the company dashboard from rendering a missing company name as undefined.

Change:

• Use a trimmed company name when present
• Fall back to there so the heading renders Welcome back, there for fresh signups without a company name
• Preserve the existing greeting when company.name is set

Verified:

• corepack pnpm --filter frontend exec eslint app/app/company/page.tsx
• corepack pnpm --filter frontend test (217 tests passed)

Note: corepack pnpm --filter frontend lint currently fails on pre-existing lint errors in unrelated files; the modified file passes ESLint directly.

[vercel]

Someone is attempting to deploy a commit to the weareghbounty-6269's projects Team on Vercel.

A member of the Team first needs to authorize it.

[eutv2022]

Note on the Vercel bot comment: that appears to be only the preview deployment authorization for the GHBounty Vercel team. It is not related to this code change.

Local verification for this PR:

• corepack pnpm --filter frontend exec eslint app/app/company/page.tsx ?
• corepack pnpm --filter frontend test ? 217 tests passed

corepack pnpm --filter frontend lint still reports pre-existing unrelated lint errors across the repo, but the modified file is lint-clean.