feat: improve analysis scheduling, move accuracy, and review interactions

[wimi321]

Performance: analysis scheduler / persistent engine mode

• Adds a prioritized analysis scheduler for live, teacher, quick, and background KataGo work.
• Adds configurable KataGo engine mode: auto, persistent, spawn.
• Keeps spawn-per-batch fallback intact unless persistent mode is explicitly forced.
• Exposes scheduler telemetry through IPC/preload for future UI status surfaces.

Accuracy: move classification 2.0 / PV confidence / evidence bundle

• Adds structured moveClassification on KataGoMoveAnalysis.
• Adds pvConfidence with strong / medium / weak / unstable evidence levels.
• Adds a compact teaching evidence bundle so teacher output can downgrade wording when evidence is thin.
• Preserves existing judgement and tracePacket compatibility.

UX: timeline navigator / board PV interaction foundation

• Adds timeline review helper contracts for key move ranking and range navigation.
• Adds board PV preview/lock/step helper contracts.
• Adds teacher evidence chip helper for later UI integration without expanding App.tsx.

Verification

• pnpm install --frozen-lockfile
• pnpm test
• pnpm typecheck
• pnpm build
• pnpm check:teacher-quality