fix(mining): remediate mining-tab audit (22 findings) — crash-safety, async control, validation, math

Fixes all 22 confirmed findings from the mining-tab audit (10 Medium, 12 Low; 0 Critical/High),
adversarially reviewed (6 follow-ups found + fixed, incl. the review-caught idle-auto-start bypass
and a wrong benchmark-restore condition).

Crash-safety & lifecycle:
- M-04: join a stale/finished monitor thread in XmrigManager::start() and ~XmrigManager so an xmrig
  crash-then-restart (or quit) no longer std::terminate()s the wallet.
- L-03/L-10: surface an unexpected miner exit once and clear the stale running flag.

UI never blocks (M-03/L-06/L-08/L-09/L-13): pool start/stop now run on a dedicated serialized FIFO
mining-control thread (joined before teardown), so the ~13 call sites don't block the render thread on
stop()'s SIGTERM->SIGKILL->join; the spawn result marshals back to the UI.

Miner-process / pool trust boundary:
- M-01: validate the payout address (util::isValidRecipientAddress) at EVERY start path — the UI gate
  AND App::startPoolMining() (idle auto-start / thread scaling) — so a stale/wrong-chain address can't
  silently lose rewards.
- M-09: SSRF guard skips the background pool-stats GET for loopback/private/link-local/single-label hosts.
- M-02/L-02: cap the pool-stats + xmrig-API HTTP response bodies.
- L-01: write the xmrig config 0600 at creation (POSIX open with mode) — no world/group-readable window.
- M-10: reject shell-metacharacter binary paths before the version popen (excluding '()' so Program Files
  (x86) still works).

Solo mining: M-06/M-08 clamp thread count to [1, cores] at the setgenerate/xmrig boundary; M-07 notify +
don't lie on stop failure.

Correctness: L-05 block-time constant 75->150s (chainparams); M-05 discloses pool-mode "Est. Daily" as a
rough solo-equivalent; L-04/L-11/L-12 benchmark lifecycle (cancel on nav-away / mode-switch with restore,
skip rebalance mid-benchmark); L-07 honor cancel mid-extract in both the xmrig and daemon updaters.

Two new i18n keys back-filled across all 8 languages; CJK subset font rebuilt for the new glyphs.
Verified across full-node, lite, and Windows builds; tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/mining_earnings.cpp

@@ -104,7 +104,10 @@ void RenderMiningEarnings(App* app, const WalletState& state, const MiningInfo&
             }
         }
 
-        // Use pool hashrate for EST. DAILY when in pool mode
+        // Est. Daily = expected reward for YOUR own hashrate share of the network. In pool mode this uses
+        // your local miner rate (pool_mining.hashrate_10s), NOT the pool's aggregate rate: pool payouts are
+        // share-proportional, so your expected daily is the same solo-equivalent value (a rough estimate,
+        // before the pool fee). Using the pool's total rate here would show the POOL's earnings, not yours. (M-05)
         double estHashrate = s_pool_mode ? state.pool_mining.hashrate_10s : mining.localHashrate;
         double est_hours_2 = EstimateHoursToBlock(estHashrate, mining.networkHashrate, mining.difficulty);
         double estDailyBlocks = (est_hours_2 > 0) ? (24.0 / est_hours_2) : 0.0;
@@ -218,12 +221,15 @@ void RenderMiningEarnings(App* app, const WalletState& state, const MiningInfo&
                 snprintf(estVal, sizeof(estVal), "~%.4f", estDaily);
             else
                 snprintf(estVal, sizeof(estVal), "N/A");
+            // Disclose in pool mode that Est. Daily is a rough solo-equivalent (before the pool fee), so the
+            // number isn't silently mismatched to its plain "Est. Daily" label. (M-05)
+            const char* estSub = (s_pool_mode && estActive) ? TR("mining_est_daily_pool_sub") : nullptr;
 
             EarningsEntry entries[] = {
                 { TR("mining_today"),      todayVal,      todaySub,      greenCol2 },
                 { TR("mining_yesterday"),  yesterdayVal,   yesterdaySub,   OnSurface() },
                 { TR("mining_all_time"),   allVal,         allSub,         OnSurface() },
-                { TR("mining_est_daily"), estVal,         nullptr,        estActive ? greenCol2 : OnSurfaceDisabled() },
+                { TR("mining_est_daily"), estVal,         estSub,         estActive ? greenCol2 : OnSurfaceDisabled() },
             };
 
             for (int ei = 0; ei < numCols; ei++) {