038 — Collapse ProposalReader into PolledReader<Proposal[]>

[archae0pteryx]

038 — Collapse ProposalReader into PolledReader<Proposal[]>

What to build

Mirror of issue 037 for the Proposal catalog. ProposalReader (src/api/proposals.ts) is the same shape as PolledReader<T>. useProposals (src/hooks/useProposals.ts) is a 22-line rename hop.

Collapse: tauriProposalReader and fixtureProposalReader return PolledReader<readonly Proposal[]>; useProposals is deleted; callers use usePolledReader<readonly Proposal[]>.

Changes

• src/api/proposals.ts — delete ProposalReader (or alias to PolledReader<readonly Proposal[]>). Keep ProposalDecisionResult, ProposalEdit, ProposalWriter — those are write-side, unrelated.
• src/api/tauriProposalReader.ts — return PolledReader<readonly Proposal[]>. Rename list → read.
• src/api/fixtureProposalReader.ts — same rename.
• src/hooks/useProposals.ts — delete.
• src/hooks/useAppState.ts (line 29) — call usePolledReader(proposalReader); destructure value as proposals. ProposalsState becomes PolledState<readonly Proposal[]>.
• src/hooks/useAppState.test.tsx — update if reader signatures changed.

Out of scope

• Focus and caps pipelines (037, 039).
• Generic factory (040).
• ProposalWriter — unchanged.

Completion promise

The Proposal catalog flows through one reader interface and one polling hook. ProposalReader and useProposals no longer exist; reads go directly through usePolledReader<readonly Proposal[]>.

Acceptance criteria

• ProposalReader interface deleted (or aliased only).
• src/hooks/useProposals.ts deleted.
• tauriProposalReader and fixtureProposalReader return PolledReader<readonly Proposal[]>.
• useAppState.ts uses usePolledReader directly for proposals.
• All proposal-related tests still green; no behavior change.
• task check green.

Blocked by

037 — same pattern, do Focus first to validate the call-site shape.