Add periodic PPLNS weight dump for cross-implementation comparison

Identified: c2pool's generate_share_transaction includes 3 addresses
(including c2pool miner) while p2pool has only 2. C2pool's chain tip
alternates between own shares and p2pool shares. When verifying a share
whose prev_hash is a c2pool share, the PPLNS walk includes c2pool's
miner address — but p2pool never has these shares in its chain.

Fix: generate_share_transaction should exclude c2pool's own unverified
shares from the PPLNS walk, OR c2pool should not add own shares to the
tracker until they're accepted by peers.

Also reverted p2pool bootstrap 'hardest bits' which broke share rate.

Author: frstrtr

src/impl/ltc/share_check.hpp

@@ -875,6 +875,26 @@ uint256 generate_share_transaction(const ShareT& share, TrackerT& tracker, bool
 
     std::map<std::vector<unsigned char>, uint64_t> amounts;
 
+    // Periodic dump of PPLNS weights for cross-impl comparison
+    {
+        static auto last_amt_dump = std::chrono::steady_clock::now() - std::chrono::seconds(60);
+        auto now_d = std::chrono::steady_clock::now();
+        if (now_d - last_amt_dump > std::chrono::seconds(30) && weights.size() >= 2) {
+            last_amt_dump = now_d;
+            LOG_INFO << "[PPLNS-AMT] subsidy=" << subsidy
+                     << " total_weight=" << total_weight.GetLow64()
+                     << " don_weight=" << total_donation_weight.GetLow64()
+                     << " addrs=" << weights.size()
+                     << " prev=" << prev_hash.GetHex().substr(0, 16);
+            for (auto& [s, w] : weights) {
+                uint64_t a = (total_weight.IsNull()) ? 0 :
+                    (uint288(subsidy) * w / total_weight).GetLow64();
+                LOG_INFO << "[PPLNS-AMT]   weight=" << w.GetLow64()
+                         << " amount=" << a;
+            }
+        }
+    }
+
     if (!total_weight.IsNull())
     {
         for (auto& [script, weight] : weights)