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/fr.json

@@ -1308,6 +1308,8 @@
     "mining_est_block": "Bloc est.",
     "mining_est_daily": "Est. quotidien",
     "mining_est_daily_pool_sub": "équivalent solo approximatif, avant les frais du pool",
+    "mining_est_daily_sub": "moy.",
+    "mining_est_daily_sub_net": "moy., net",
     "mining_filter_all": "Tout",
     "mining_filter_tip_all": "Afficher tous les gains",
     "mining_filter_tip_pool": "Afficher uniquement les gains du pool",
@@ -2108,6 +2110,9 @@
     "tt_low_spec": "Désactiver tous les effets visuels lourds\\nRaccourci : Ctrl+Shift+Down",
     "tt_merge": "Consolider plusieurs UTXOs vers une adresse",
     "tt_mine_idle": "Démarrer le minage automatiquement quand le\\nsystème est inactif (aucune entrée clavier/souris)",
+    "tt_mining_est_daily": "Une moyenne statistique à long terme pour votre part actuelle de hashrate dans le réseau. Les récompenses réelles de minage arrivent au hasard (Poisson) — souvent rien pendant longtemps, puis une somme — ce n'est donc PAS un revenu quotidien régulier.",
+    "tt_mining_est_daily_fee_fmt": "Affiché après les %.1f%% de frais de pool.",
+    "tt_mining_est_daily_nofee": "Affiché avant les frais de pool (frais inconnus pour ce pool).",
     "tt_new_mining_address": "Crée une adresse transparente (R…) pour les récompenses de minage en solo. Elle ne peut pas recevoir de paiements — partagez une adresse blindée pour cela.",
     "tt_noise": "Intensité de texture grainée (0% = désactivé, 100% = maximum)",
     "tt_open_app_dir": "Ouvrir le dossier ObsidianDragon (paramètres, thèmes, journaux) dans le gestionnaire de fichiers",