feat(miner-selfimprove): calibration dashboard extension panel — accuracy trend view

[JSONbored]

This item extends the calibration dashboard (#4261, "calibration dashboard — predicted-gate accuracy vs real pr_outcome, read-only", filed in this same batch) into a panel inside the miner's browser extension surface, showing an accuracy trend over time (not just the current-snapshot view the base dashboard renders).

This item has two real dependencies and is not startable in isolation:

1. feat(miner-selfimprove): calibration dashboard — predicted-gate accuracy vs real pr_outcome, read-only #4261, the calibration dashboard item — this panel is a trend-over-time extension of that dashboard's single-snapshot Phase7CalibrationLoopResult view (packages/gittensory-engine/src/phase7-calibration-loop.ts:80-102). A trend view needs a series of historical results, not one — which in turn depends on the local prediction-ledger item (feat(miner-selfimprove): local prediction-ledger schema — record every predicted-gate verdict for later scoring #4263) actually accumulating history to trend over.
2. The Phase 6 browser-extension-scaffold item — feat(miner-extension): scaffold browser extension surface (tracker 🧩 Wave 2 — Analyze, Plan, Create & Deploy (HELD tracker) #2353, Phase 6). At the time of filing this issue, no such issue has been filed yet (searched JSONbored/gittensory open/closed issues for "browser extension scaffold" / "miner-extension" / "extension surface" and swept issues created in the last hour — the only matches are old, already-closed extension work from feat(extension): scaffold GitHub overlay browser extension #145/roadmap(phase 2): maintainer trust and browser extension #235/roadmap(pillar 2): surfaces — browser-extension rebuild & notifications #527/feat(extension): rebuild as dual-audience overlay (WXT + React) #534, none of which are this scaffold). This panel cannot be built until that scaffold exists to build a panel inside.

Filing this now so the dependency chain is visible in the tracker, but implementation should wait for both prerequisites.

Deliverables

• Do not start implementation until (a) feat(miner-selfimprove): calibration dashboard — predicted-gate accuracy vs real pr_outcome, read-only #4261 has landed with a stable Phase7CalibrationLoopResult-consuming view/API, and (b) the Phase 6 browser-extension-scaffold item has landed with a panel-registration surface.
• A trend view (sparkline or simple time-series chart) of combined calibration accuracy vs the documented baseline (DOCUMENTED_CALIBRATION_BASELINE = 0.62, phase7-calibration-loop.ts:11) over some rolling window, sourced from accumulated historical snapshots (not a single live call).
• Read-only — consistent with every other Phase 7 contributor-safe item in this batch; this panel must not expose any control that adjusts calibration weights, thresholds, or autonomy level (that authority is maintainer-only, see maintainer: personalized gate-prediction tuning per contributor/miner history #2349/maintainer: fleet-wide anti-farming detector — flag a miner/fleet gaming the calibration score #2350/maintainer: wire calibration accuracy into the live auto-tune circuit-breaker for miner-originated PRs #2352).
• Graceful empty/sparse-history state (a brand-new install has zero snapshots to trend) rather than a broken/empty chart.
• Tests for the trend-rendering logic against fixture snapshot series (at least: empty, single-point, multi-point improving, multi-point degrading).

References

• feat(miner-selfimprove): calibration dashboard — predicted-gate accuracy vs real pr_outcome, read-only #4261 (calibration dashboard, this batch — the single-snapshot view this panel extends into a trend)
• feat(miner-selfimprove): local prediction-ledger schema — record every predicted-gate verdict for later scoring #4263 (local prediction-ledger schema, this batch — the accumulated-history source a trend needs)
• Tracker 🧩 Wave 2 — Analyze, Plan, Create & Deploy (HELD tracker) #2353, Phase 6: feat(miner-extension): scaffold browser extension surface (not yet filed as of this writing — searched and confirmed absent)
• packages/gittensory-engine/src/phase7-calibration-loop.ts:11 (DOCUMENTED_CALIBRATION_BASELINE)
• packages/gittensory-engine/src/phase7-calibration-loop.ts:80-102 (Phase7CalibrationLoopResult, the single-snapshot shape a trend needs to accumulate)
• maintainer: personalized gate-prediction tuning per contributor/miner history #2349, maintainer: fleet-wide anti-farming detector — flag a miner/fleet gaming the calibration score #2350, maintainer: wire calibration accuracy into the live auto-tune circuit-breaker for miner-originated PRs #2352 (maintainer-only calibration-adjustment authority — why this panel stays read-only)

[linear-code]

JSO-3255