cff6e61d2f
Caps the stacked stability work (stages 1-6). Verification only — ZERO production code change (git diff against fix/stage-6-healthcheck touches only these two files). - tests/test_stage7_integration.py (8 cross-stage integration tests via TestClient + a mocked TelegramClient, no network): Range at the /media route level (206/206/416 through get_media -> prepare_file_response -> FileResponse); /ping stays prompt and issues zero TG RPC while a slow op is parked; in-flight dedup shares one download and drains _inflight after completion AND after request cancellation (no stuck key / hung waiter); str(channel) access-time hit -> flush -> the bulk UPDATE lands on the seeded row (mutation-verified: transposing the key columns reds it). - docs/stability-verification.md: per-stage DoD -> evidence mapping (test or "operator observation" for prod-only items), the exact manual curl/lsof scenarios for the operator to run post-deploy, the diag-log signals to watch, and the per-stage independent-commit rollback plan. Full integrated suite: 260 passed (252 baseline + 8). The prod deploy + live diag-log observation (plan items 3-4) are the operator's call — this stage does not deploy. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>