fix: Use BC resources directly for teammate timesheet view (#189)

[akash2017sky]

Closes #189

Summary

• Teammate dropdown on the Time tab now fetches BC resources (where useTimeSheet=true) instead of employees — resources are the entities that own timesheets, so we can fetch them by resource.number directly.
• getTeammateEntries no longer relies on getResourceByEmail, which silently failed whenever an employee's email was missing or its local-part didn't match the resource's timeSheetOwnerUserId convention.
• Same pattern already used on the Team page (TeamList.tsx), so this brings the two views into agreement.

Root cause

getTeammateEntries called bcClient.getResourceByEmail(teammate.email), which forwards to getResourceForCurrentUser. That helper derives a BC User ID by uppercasing the part before @ and filters resources by timeSheetOwnerUserId. It works for the logged-in user (their UPN follows the convention) but is unreliable for teammates pulled from /employees. When the lookup returned null, the function returned [] — the empty state seen in the bug report.

Test plan

• Type check passes (bun run typecheck)
• Verified locally: own timesheet still loads
• Verify locally: selecting a teammate from the dropdown loads their timesheet entries
• Verify "(My Name)" still appears next to "My Timesheet" in the dropdown
• Verify dropdown hides when the user is the only resource with useTimeSheet=true

Notes

• The teammate read-only banner now shows the resource number (BC code) instead of jobTitle, since jobTitle is an employee-only field.
• getResourceByEmail is still in bcClient.ts (used by TeamList.tsx for the current user's own resource); not removing it in this PR to keep the change focused.

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