Fix stats command flow and tracking metrics regressions

- Route default `subminer stats` through attached `--stats`; keep daemon path for `--background`/`--stop`
- Update overview metrics: lookup rate uses lifetime Yomitan lookups per 100 tokens; new words dedupe by headword
- Suppress repeated macOS `Overlay loading...` OSD during fullscreen tracker flaps and improve session-detail chart scaling
- Add/adjust launcher, tracker query, stats server, IPC, overlay, and stats UI regression tests; add changelog fragments

backlog/tasks/task-182.2 - Improve-session-detail-known-word-chart-scaling.md

@@ -0,0 +1,66 @@
+---
+id: TASK-182.2
+title: Improve session detail known-word chart scaling
+status: Done
+assignee:
+  - codex
+created_date: '2026-03-19 20:31'
+updated_date: '2026-03-19 20:52'
+labels:
+  - bug
+  - stats
+  - ui
+dependencies: []
+references:
+  - >-
+    /Users/sudacode/projects/japanese/SubMiner/stats/src/components/sessions/SessionDetail.tsx
+  - >-
+    /Users/sudacode/projects/japanese/SubMiner/stats/src/lib/session-detail.test.tsx
+parent_task_id: TASK-182
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Adjust the expanded session-detail known-word percentage chart so the vertical range reflects the session's actual percent range instead of always spanning 0-100. Keep the chart easier to read while preserving the percent-based tooltip/legend behavior already used in the stats UI.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Expanded session detail scales the known/unknown percent chart to the session's observed percent range instead of hard-coding a 0-100 top bound
+- [x] #2 The chart keeps a small headroom above the highest observed known-word percent so the line remains visually readable near the top edge
+- [x] #3 Automated frontend coverage locks the new percent-domain behavior and preserves existing session-detail rendering
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add a focused frontend regression test for the session-detail ratio chart domain calculation, covering a session whose known-word percentage stays in a narrow band below 100% and expecting a dynamic top bound with headroom.
+2. Update `stats/src/components/sessions/SessionDetail.tsx` to compute a dynamic percent-axis domain and matching ticks for the ratio chart, keeping the lower bound at 0%, adding modest padding above the highest known percentage, rounding to clean tick steps, and capping at 100%.
+3. Apply the computed percent-axis bounds consistently to the right-side Y axis and the session chart pause overlays so the visual framing stays aligned.
+4. Run targeted frontend tests and the SubMiner verification helper on the touched files, then record results and any blockers in the task.
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implemented dynamic known-percentage axis scaling in `stats/src/components/sessions/SessionDetail.tsx`: the ratio chart now keeps a 0% floor, uses the highest observed known percentage plus 5 points of headroom for the top bound, rounds that bound up to clean 10-point ticks, caps at 100%, and enables `allowDataOverflow` so the stacked area chart actually honors the tighter domain.
+
+Added frontend regression coverage in `stats/src/lib/session-detail.test.tsx` for the axis-max helper, covering both a narrow-band session and near-100% cap behavior.
+
+Added user-visible changelog fragment `changes/2026-03-19-session-detail-chart-scaling.md`.
+
+Verification: `bun test stats/src/lib/session-detail.test.tsx` passed; `bun run typecheck` passed; `bun run changelog:lint` passed; `bash .agents/skills/subminer-change-verification/scripts/verify_subminer_change.sh --lane core stats/src/components/sessions/SessionDetail.tsx stats/src/lib/session-detail.test.tsx` ran and passed `typecheck` but failed `bun run test:fast` on a pre-existing unrelated issue in `scripts/update-aur-package.test.ts` / `scripts/update-aur-package.sh` (`mapfile: command not found`). Artifacts: `.tmp/skill-verification/subminer-verify-20260319-134440-JRHAUJ`.
+
+Docs decision: no internal docs update required; the behavior change is localized UI presentation with no API/workflow change. Changelog decision: yes, required and completed because the fix is user-visible.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Improved expanded session-detail chart readability by replacing the fixed 0-100 known-word percentage axis with a dynamic top bound based on the session’s highest observed known percentage plus modest headroom, rounded to clean ticks and capped at 100%. The ratio chart now also enables `allowDataOverflow` so Recharts preserves the tighter percent domain even though the stacked known/unknown areas sum to 100%.
+
+Added frontend regression coverage for the new axis-max behavior and a changelog fragment for the user-visible stats fix.
+
+Verification: `bun test stats/src/lib/session-detail.test.tsx`, `bun run typecheck`, and `bun run changelog:lint` passed. The SubMiner verification helper’s `core` lane also passed `typecheck`, but `bun run test:fast` remains red on a pre-existing unrelated bash-compat failure in `scripts/update-aur-package.test.ts` / `scripts/update-aur-package.sh` (`mapfile: command not found`).
+<!-- SECTION:FINAL_SUMMARY:END -->