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## Summary Follow-up to [#8931](https://github.com/block/buzz/pull/8931), from Wes's [review note](https://github.com/block/buzz/pull/8931#discussion_r4456891410). [#8931](https://github.com/block/buzz/pull/8931) replaced the per-eviction scan in `VerifiedProfilesNotifier.track` with `keys.first`. That was much cheaper than main, but not constant time: removing from a Dart map leaves deleted slots, and each new `keys` iterator walks past them. One `track` call that overflows the 1,024-subject cap by E subjects still costs about E²/2 slot checks. Wes measured ~3 ms at 4,300 subjects, 62 ms at 8,600 and 205 ms at 17,200. Eviction now takes the overflow from a single iteration (`keys.take(overflow).toList()`), so it's linear. Which subjects are kept doesn't change: still the 1,024 most recently inserted. The [#8931](https://github.com/block/buzz/pull/8931) eviction test counted keys yielded by the map, which `keys.first` keeps at one per eviction, so it couldn't fail on the quadratic path. It now counts iterations started over the interest map and expects exactly one per `track` call. Main's scan and the merged `keys.first` loop both start one per eviction. ### Testing - Falsification: with the merged `keys.first` loop restored, the new test fails (`Expected: <1>, Actual: <3276>`). With this change it passes. - `flutter test test/shared/verified_profiles/`: 31 passed. The existing "keeps the 1,024 most recently tracked subjects" journey still passes, so retention is unchanged. - `just mobile-check`: clean. - `just mobile-test`: 4,227 Flutter tests passed, 40 skipped, plus 4 push and 27 crypto tests. - Automated app run: installed this build on an iOS 27 simulator (iPhone 17 Pro) signed in to a Builderlab community, opened the inbox, a channel timeline with images and the image viewer, and the channel details member list, which all track verified-profile subjects. No errors. That community is small (30 members), so the overflow path itself is covered by the unit tests, not the app run. - Agent review: an independent agent review found no blockers. - Human test: waived under the mobile testing exception; the automated app run above replaces it. Not covered: Android, and no new device profile (Wes's AOT numbers above are the cost model; this removes the E² term). buzz-review-completed 🤖 Generated with [Claude Code](https://claude.com/claude-code) Signed-off-by: Tom Brow <tomb@squareup.com> Co-authored-by: Tom Brow <tomb@squareup.com> Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>