fix(mining): make "Est. Daily" honest about variance and fees

The mining "Est. Daily" was a solo expected-value (your hashrate share x
blocks/day x a fixed block reward) rendered in the same green as the real
Today / Yesterday / All-Time earnings, off an instantaneous hashrate and
gross of pool fees. It read like a dependable daily income when it is a
long-run statistical average with huge (Poisson) variance.

Framing:
- The estimate is now drawn in a neutral colour, not the green "money
  earned" colour (the actual mined totals stay green).
- A sub-label in BOTH modes marks it as an average ("avg", or "avg, net"
  in pool mode when the fee is applied), replacing the pool-only
  "before pool fee" note.
- A hover tooltip over the column explains the variance ("often nothing
  for long stretches, then a lump - NOT a steady daily income") and the
  fee status (after the N% fee / before the fee when unknown / nothing for
  solo and 0%-fee pools).

Accuracy:
- Uses a trailing-average hashrate instead of the instantaneous / 10s
  snapshot: pool prefers hashrate_15m (then 60s, then 10s); solo uses the
  mean of hashrate_history once there are >=10 samples, else the instant
  rate. This stops a spike or a momentary dip from swinging the figure.
- Subtracts the known pool fee so pool-mode figures are net; synthetic or
  unmatched pools stay gross and the tooltip says the fee is unknown.

The static block reward and true pool-reported earnings are intentionally
out of scope (the latter needs a new pool-API field). New i18n keys are
translated into all eight locales; the CJK subset font is rebuilt for the
three new glyphs. Builds + test suites pass on both variants.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

res/lang/ko.json

@@ -1308,6 +1308,8 @@
     "mining_est_block": "예상 블록",
     "mining_est_daily": "예상 일일 수익",
     "mining_est_daily_pool_sub": "대략적인 솔로 환산, 풀 수수료 전",
+    "mining_est_daily_sub": "평균",
+    "mining_est_daily_sub_net": "평균, 순",
     "mining_filter_all": "전체",
     "mining_filter_tip_all": "모든 수익 표시",
     "mining_filter_tip_pool": "풀 수익만 표시",
@@ -2108,6 +2110,9 @@
     "tt_low_spec": "모든 고부하 시각 효과 비활성화\\n단축키: Ctrl+Shift+Down",
     "tt_merge": "여러 UTXO를 하나의 주소로 통합",
     "tt_mine_idle": "시스템이 유휴 상태(키보드/마우스 입력 없음)일 때\\n자동으로 채굴 시작",
+    "tt_mining_est_daily": "네트워크에서 현재 해시레이트 비중에 대한 장기 통계 평균입니다. 실제 채굴 보상은 무작위(푸아송)로 도착하여 오랫동안 아무것도 없다가 한꺼번에 들어오는 경우가 많으므로, 이는 꾸준한 일일 수입이 아닙니다.",
+    "tt_mining_est_daily_fee_fmt": "%.1f%% 풀 수수료를 제외하고 표시됩니다.",
+    "tt_mining_est_daily_nofee": "풀 수수료를 제외하기 전 값입니다(이 풀의 수수료는 알 수 없음).",
     "tt_new_mining_address": "솔로 채굴 보상용 투명(R…) 주소를 만듭니다. 결제는 받을 수 없으니, 결제용으로는 차폐 주소를 공유하세요.",
     "tt_noise": "그레인 텍스처 강도 (0% = 끔, 100% = 최대)",
     "tt_open_app_dir": "파일 관리자에서 ObsidianDragon 폴더(설정, 테마, 로그)를 엽니다",