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/de.json

@@ -1308,6 +1308,8 @@
     "mining_est_block": "Gesch. Block",
     "mining_est_daily": "Gesch. täglich",
     "mining_est_daily_pool_sub": "grobe Solo-Äquivalenz, vor Pool-Gebühr",
+    "mining_est_daily_sub": "Ø",
+    "mining_est_daily_sub_net": "Ø, netto",
     "mining_filter_all": "Alle",
     "mining_filter_tip_all": "Alle Einnahmen anzeigen",
     "mining_filter_tip_pool": "Nur Pool-Einnahmen anzeigen",
@@ -2108,6 +2110,9 @@
     "tt_low_spec": "Alle aufwendigen visuellen Effekte deaktivieren\\nHotkey: Ctrl+Shift+Down",
     "tt_merge": "Mehrere UTXOs einer Adresse zusammenführen",
     "tt_mine_idle": "Mining automatisch starten, wenn das\\nSystem inaktiv ist (keine Tastatur-/Mauseingabe)",
+    "tt_mining_est_daily": "Ein langfristiger statistischer Durchschnitt für Ihren aktuellen Hashrate-Anteil am Netzwerk. Echte Mining-Belohnungen kommen zufällig (Poisson) – oft lange nichts, dann ein Batzen – das ist also KEIN gleichmäßiges Tageseinkommen.",
+    "tt_mining_est_daily_fee_fmt": "Angezeigt nach der %.1f%% Pool-Gebühr.",
+    "tt_mining_est_daily_nofee": "Vor Abzug der Pool-Gebühr angezeigt (Gebühr für diesen Pool unbekannt).",
     "tt_new_mining_address": "Erstellt eine transparente Adresse (R…) für Solo-Mining-Belohnungen. Sie kann keine Zahlungen empfangen – teilen Sie dafür eine abgeschirmte Adresse.",
     "tt_noise": "Körnungstextur-Intensität (0% = aus, 100% = maximum)",
     "tt_open_app_dir": "Den ObsidianDragon-Ordner (Einstellungen, Themes, Logs) im Dateimanager öffnen",