feat(intake,review): duplicate handling in the UI

[Fluory]

Goal

When a request looks like a duplicate, the clerk sees the original and decides – nothing is discarded silently and nothing is exported twice.

Acceptance criteria

• A possible duplicate shows a banner linking the original request
• Clerk decides: continue processing or reject as duplicate (reason stored, audited)
• A request rejected as duplicate can never be exported

Not part of this task

• Near-duplicate similarity search

Affected areas

• src/features/intake/
• src/features/review/
• src/features/requests/

Test plan

Criterion	Check
decision flow	integration test
no export after reject	integration test

Security/Privacy affected?

Tenant-scoped: duplicates are only detected within the same company.

Epic: #18 · Architecture: docs/decisions/ADR-0001-pilot-architecture.md

[Fluory]

Claimed by @Fluory (Claude Code, overnight run) on branch claude/feat-duplicates-27 – stacked on #26 (restacked before the PR). Code and tests are pushed.

decision-needed – when does the clerk decide on a possible duplicate? I took the most reversible option: a flagged request is still processed automatically (cheap, and nothing is lost), and the decision happens at review. The request page shows a banner linking the original with "Kein Duplikat – weiter bearbeiten" and "Als Duplikat ablehnen" (reason required, audited). Approval is refused while a flagged request is undecided, so nothing is exported twice by accident. Rejection is possible in NEW (a queued job then skips it), REVIEW and ERROR (processing stage), but not while a worker holds the request. The alternative is to hold flagged requests before processing until a clerk decides; that saves AI cost but delays every true positive.

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Generated by Claude Code