[#68] Add error state rendering to dashboards

[realproject7]

Summary

• Surface Supabase query errors by throwing from fetch functions so useQuery captures them
• Render user-visible error messages ("Failed to load storylines/donations. Please try again.") in both writer and reader dashboards
• Previously, failed queries silently showed the empty state with no indication of failure

Fixes #68

Test plan

• Simulate Supabase failure (e.g. invalid anon key) and verify error message appears on both dashboards
• Verify normal operation unchanged (successful queries render data as before)
• npm run lint and npm run typecheck pass

🤖 Generated with Claude Code

[project7-interns]

LGTM. Clean, minimal error handling — Supabase errors are properly thrown so useQuery captures them, and both dashboards render user-visible error messages. Pattern is consistent across both files. Approved.

[project7-interns]

Verdict: REQUEST CHANGES

Summary

The PR correctly surfaces React Query errors, but both dashboards still render their normal empty-state copy when a fetch fails, which gives users contradictory feedback.

Findings

• [medium] The writer dashboard defaults storylines to [], so when useQuery errors it renders both "Failed to load storylines" and "No storylines yet." at the same time. That is the same silent-empty-state bug in a different form, because an error is still presented as if the user simply has no data.
  • File: src/app/dashboard/writer/page.tsx:28
  • Suggestion: Gate the empty state on !error, or return early for the error state before rendering the list container.
• [medium] The reader dashboard has the same contradiction: on donation query failure it shows the error message and then No donations yet. because donations falls back to an empty array.
  • File: src/app/dashboard/reader/page.tsx:44
  • Suggestion: Gate the empty state on !error, or return early for the error state before rendering the list container.

Decision

Requesting changes because the error-state UX is still incorrect in both dashboards.

[project7-interns]

LGTM. Empty-state rendering properly gated on !error in both dashboards — no more dual rendering on failure. Approved.

[project7-interns]

Verdict: APPROVE

Summary

The dashboards now surface Supabase query failures and no longer render the empty state alongside the error message. The PR matches issue #68 and lint-and-typecheck is passing.

Findings

• none

Decision

Approving because both writer and reader dashboards now present a correct, user-visible error state without contradictory empty-state rendering.