v0.0.0.1 feat: add duplicate upload rejection reason

[ohld]

Summary

• Add a 🔁 Баян rejection button to the existing upload-review reason row.
• Route reject_duplicate through the normal rejection path and store MemeStatus.REJECTED.
• Notify the uploader with the existing localized message explaining that the meme is already in the collection.

Test coverage

review_keyboard()                         moderator clicks «🔁 Баян»
├─ button in rejection-reason row         ├─ callback is accepted
└─ reject_duplicate callback              ├─ status becomes REJECTED
                                           ├─ review caption says «Баян»
handler                                   └─ uploader receives duplicate notice
├─ recognizes the new action
├─ maps it to localized copy              localization
└─ uses the existing rejection flow       ├─ English checked
                                           └─ Russian checked

Coverage: 6/6 changed behavior paths tested (100%); no untested gaps identified.

Verification

• pytest tests/tgbot/test_upload_moderation.py -q — 8 passed.
• Full CI-like suite with temporary PostgreSQL and Redis — 736 passed, 2 skipped.
• ruff check src/ tests/ — passed.
• ruff format --check src/ tests/ — passed.
• git diff --check — passed.

Pre-landing review

• Testing, maintainability, performance, and independent adversarial reviews completed.
• No findings against the production change.
• One informational test-duplication suggestion was intentionally deferred: this is the second repetition, and the project preference is to keep MVP test setup inline until a third repetition justifies extraction.
• Review also surfaced a pre-existing generic race between concurrent moderation callbacks. It affects existing approve/reject actions and is not introduced or expanded by this PR; it should be handled separately.

Scope and documentation

• Scope audit: clean; only the moderation handler, its tests, and release metadata changed.
• No database migration, public API, frontend, or infrastructure changes.
• No matching product-plan or TODO item was found.
• Documentation release check: no README/spec/architecture updates needed; the existing moderation docs and new changelog entry cover the change.

Test plan

The release test plan is recorded in the local gstack project artifacts. The user-visible path is covered at callback level because this workflow runs inside the private Telegram moderation chat rather than a browser UI.

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Generated with Codex

[ohld]

STAFF ENGINEER REVIEW: APPROVED — Upload duplicate rejection reason is clean.

Checked the upload-review callback path, duplicate rejection mapping, localization, payout side effects, sensitive upload/moderation surface, and public-repo secret guard. The new reject_duplicate action reuses the existing rejection path and stores MemeStatus.REJECTED; no distinct authorization, payout, SQL, or secret-handling regression found.

Verification: GitHub lint and test checks are green on the PR head. Local targeted pytest was attempted from an isolated worktree but host collection failed because the ambient DATABASE_URL dialect is postgres; CI uses the correct postgresql+asyncpg URL and passed. Codex review: clean, no [P1] findings.

[ohld]

✅ Approved + merged.