v1.1.0: explorer tab, bootstrap fixes, full theme overlay merge

Explorer tab:
- New block explorer tab with search, chain stats, mempool info,
  recent blocks table, block detail modal with tx expansion
- Sidebar nav entry, i18n strings, ui.toml layout values

Bootstrap fixes:
- Move wizard Done handler into render() — was dead code, preventing
  startEmbeddedDaemon() and tryConnect() from firing post-wizard
- Stop deleting BDB database/ dir during cleanup — caused LSN mismatch
  that salvaged wallet.dat into wallet.{timestamp}.bak
- Add banlist.dat, db.log, .lock to cleanup file list
- Fatal extraction failure for blocks/ and chainstate/ files
- Verification progress: split SHA-256 (0-50%) and MD5 (50-100%)

Theme system:
- Expand overlay merge to apply ALL sections (tabs, dialogs, components,
  screens, flat sections), not just theme+backdrop+effects
- Add screens and security section parsing to UISchema
- Build-time theme expansion via expand_themes.py (CMake + build.sh)

Other:
- Version bump to 1.1.0
- WalletState::clear() resets all fields (sync, daemon info, etc.)
- Sidebar item-height 42 → 36

src/util/i18n.cpp

@@ -1068,6 +1068,25 @@ void I18n::loadBuiltinEnglish()
         strings_["import_key_progress"] = "Importing %d/%d...";
         strings_["click_to_copy"] = "Click to copy";
         strings_["block_hash_copied"] = "Block hash copied";
+
+        // Explorer tab
+        strings_["explorer"] = "Explorer";
+        strings_["explorer_search"] = "Search";
+        strings_["explorer_chain_stats"] = "Chain";
+        strings_["explorer_mempool"] = "Mempool";
+        strings_["explorer_mempool_txs"] = "Transactions";
+        strings_["explorer_mempool_size"] = "Size";
+        strings_["explorer_recent_blocks"] = "Recent Blocks";
+        strings_["explorer_block_detail"] = "Block";
+        strings_["explorer_block_height"] = "Height";
+        strings_["explorer_block_hash"] = "Hash";
+        strings_["explorer_block_txs"] = "Transactions";
+        strings_["explorer_block_size"] = "Size";
+        strings_["explorer_block_time"] = "Time";
+        strings_["explorer_block_merkle"] = "Merkle Root";
+        strings_["explorer_tx_outputs"] = "Outputs";
+        strings_["explorer_tx_size"] = "Size";
+        strings_["explorer_invalid_query"] = "Enter a block height or 64-character hash";
 }
 
 const char* I18n::translate(const char* key) const