refactor: Fix includes in `index` directory

diff --git a/contrib/devtools/iwyu/bitcoin.core.imp b/contrib/devtools/iwyu/bitcoin.core.imp
index 789abcda..c3195e51 100644
--- a/contrib/devtools/iwyu/bitcoin.core.imp
+++ b/contrib/devtools/iwyu/bitcoin.core.imp
@@ -8,4 +8,9 @@
   # libc symbols.
   { "symbol": ["AT_HWCAP", "private", "<sys/auxv.h>", "public"] },
   { "symbol": ["AT_HWCAP2", "private", "<sys/auxv.h>", "public"] },
+
+  # Fixed in https://github.com/include-what-you-use/include-what-you-use/pull/1706.
+  { "symbol": ["SEEK_CUR", "private", "<cstdio>", "public"] },
+  { "symbol": ["SEEK_END", "private", "<cstdio>", "public"] },
+  { "symbol": ["SEEK_SET", "private", "<cstdio>", "public"] },
 ]
diff --git a/src/index/base.cpp b/src/index/base.cpp
index 82259ac0..b547a13c 100644
--- a/src/index/base.cpp
+++ b/src/index/base.cpp
@@ -2,10 +2,13 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <chainparams.h>
-#include <common/args.h>
 #include <index/base.h>
+
+#include <chain.h>
+#include <common/args.h>
+#include <dbwrapper.h>
 #include <interfaces/chain.h>
+#include <interfaces/types.h>
 #include <kernel/chain.h>
 #include <logging.h>
 #include <node/abort.h>
@@ -13,20 +16,31 @@
 #include <node/context.h>
 #include <node/database_args.h>
 #include <node/interface_ui.h>
+#include <primitives/block.h>
+#include <sync.h>
 #include <tinyformat.h>
+#include <uint256.h>
 #include <undo.h>
+#include <util/fs.h>
 #include <util/string.h>
 #include <util/thread.h>
+#include <util/threadinterrupt.h>
+#include <util/time.h>
 #include <util/translation.h>
 #include <validation.h>
+#include <validationinterface.h>
 
-#include <chrono>
+#include <cassert>
+#include <compare>
+#include <cstdint>
 #include <memory>
 #include <optional>
+#include <span>
 #include <stdexcept>
 #include <string>
 #include <thread>
 #include <utility>
+#include <vector>
 
 constexpr uint8_t DB_BEST_BLOCK{'B'};
 
diff --git a/src/index/base.h b/src/index/base.h
index 4131b06c..5a6f0a40 100644
--- a/src/index/base.h
+++ b/src/index/base.h
@@ -5,29 +5,41 @@
 #ifndef BITCOIN_INDEX_BASE_H
 #define BITCOIN_INDEX_BASE_H
 
+#include <attributes.h>
 #include <dbwrapper.h>
 #include <interfaces/chain.h>
-#include <interfaces/types.h>
-#include <util/string.h>
+#include <kernel/cs_main.h>
+#include <threadsafety.h>
+#include <uint256.h>
+#include <util/fs.h>
 #include <util/threadinterrupt.h>
 #include <validationinterface.h>
 
+#include <atomic>
+#include <cstddef>
+#include <memory>
+#include <optional>
 #include <string>
+#include <thread>
 
 class CBlock;
 class CBlockIndex;
 class Chainstate;
-class ChainstateManager;
-namespace interfaces {
-class Chain;
-} // namespace interfaces
 
+struct CBlockLocator;
 struct IndexSummary {
     std::string name;
     bool synced{false};
     int best_block_height{0};
     uint256 best_block_hash;
 };
+namespace interfaces {
+struct BlockRef;
+}
+namespace util {
+template <unsigned int num_params>
+struct ConstevalFormatString;
+}
 
 /**
  * Base class for indices of blockchain data. This implements
diff --git a/src/index/blockfilterindex.cpp b/src/index/blockfilterindex.cpp
index 2ccae3a2..e47e47c1 100644
--- a/src/index/blockfilterindex.cpp
+++ b/src/index/blockfilterindex.cpp
@@ -2,19 +2,39 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <map>
+#include <index/blockfilterindex.h>
 
-#include <clientversion.h>
+#include <blockfilter.h>
+#include <chain.h>
 #include <common/args.h>
 #include <dbwrapper.h>
+#include <flatfile.h>
 #include <hash.h>
-#include <index/blockfilterindex.h>
+#include <index/base.h>
+#include <interfaces/chain.h>
+#include <interfaces/types.h>
 #include <logging.h>
-#include <node/blockstorage.h>
-#include <undo.h>
-#include <util/fs_helpers.h>
+#include <serialize.h>
+#include <streams.h>
+#include <sync.h>
+#include <uint256.h>
+#include <util/check.h>
+#include <util/fs.h>
+#include <util/hasher.h>
 #include <util/syserror.h>
 
+#include <cerrno>
+#include <exception>
+#include <ios>
+#include <map>
+#include <optional>
+#include <span>
+#include <stdexcept>
+#include <string>
+#include <tuple>
+#include <utility>
+#include <vector>
+
 /* The index database stores three items for each block: the disk location of the encoded filter,
  * its dSHA256 hash, and the header. Those belonging to blocks on the active chain are indexed by
  * height, and those belonging to blocks that have been reorganized out of the active chain are
diff --git a/src/index/blockfilterindex.h b/src/index/blockfilterindex.h
index 983cf322..b1ebd55f 100644
--- a/src/index/blockfilterindex.h
+++ b/src/index/blockfilterindex.h
@@ -6,13 +6,24 @@
 #define BITCOIN_INDEX_BLOCKFILTERINDEX_H
 
 #include <attributes.h>
-#include <blockfilter.h>
-#include <chain.h>
 #include <flatfile.h>
 #include <index/base.h>
+#include <interfaces/chain.h>
+#include <sync.h>
+#include <uint256.h>
 #include <util/hasher.h>
 
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <optional>
 #include <unordered_map>
+#include <vector>
+
+class BlockFilter;
+class CBlockIndex;
+enum class BlockFilterType : uint8_t;
 
 static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
 
diff --git a/src/index/coinstatsindex.cpp b/src/index/coinstatsindex.cpp
index af798e29..f247a1d0 100644
--- a/src/index/coinstatsindex.cpp
+++ b/src/index/coinstatsindex.cpp
@@ -2,20 +2,39 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <index/coinstatsindex.h>
+
 #include <arith_uint256.h>
+#include <chain.h>
 #include <chainparams.h>
 #include <coins.h>
 #include <common/args.h>
+#include <consensus/amount.h>
 #include <crypto/muhash.h>
-#include <index/coinstatsindex.h>
+#include <dbwrapper.h>
+#include <index/base.h>
+#include <interfaces/chain.h>
+#include <interfaces/types.h>
 #include <kernel/coinstats.h>
 #include <logging.h>
-#include <node/blockstorage.h>
+#include <primitives/block.h>
+#include <primitives/transaction.h>
+#include <script/script.h>
 #include <serialize.h>
-#include <txdb.h>
+#include <uint256.h>
 #include <undo.h>
+#include <util/check.h>
+#include <util/fs.h>
 #include <validation.h>
 
+#include <compare>
+#include <ios>
+#include <limits>
+#include <span>
+#include <string>
+#include <utility>
+#include <vector>
+
 using kernel::ApplyCoinHash;
 using kernel::CCoinsStats;
 using kernel::GetBogoSize;
diff --git a/src/index/coinstatsindex.h b/src/index/coinstatsindex.h
index 7e48f4c4..ce953146 100644
--- a/src/index/coinstatsindex.h
+++ b/src/index/coinstatsindex.h
@@ -6,11 +6,18 @@
 #define BITCOIN_INDEX_COINSTATSINDEX_H
 
 #include <arith_uint256.h>
+#include <consensus/amount.h>
 #include <crypto/muhash.h>
 #include <index/base.h>
+#include <interfaces/chain.h>
+#include <uint256.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <optional>
 
 class CBlockIndex;
-class CDBBatch;
 namespace kernel {
 struct CCoinsStats;
 }
diff --git a/src/index/txindex.cpp b/src/index/txindex.cpp
index 11dd856e..63aa484c 100644
--- a/src/index/txindex.cpp
+++ b/src/index/txindex.cpp
@@ -4,14 +4,32 @@
 
 #include <index/txindex.h>
 
-#include <clientversion.h>
 #include <common/args.h>
+#include <dbwrapper.h>
+#include <flatfile.h>
+#include <index/base.h>
 #include <index/disktxpos.h>
+#include <interfaces/chain.h>
 #include <logging.h>
 #include <node/blockstorage.h>
-#include <primitives/transaction_identifier.h>
+#include <primitives/block.h>
+#include <primitives/transaction.h>
+#include <serialize.h>
+#include <streams.h>
+#include <uint256.h>
+#include <util/fs.h>
 #include <validation.h>
 
+#include <cassert>
+#include <cstdint>
+#include <cstdio>
+#include <exception>
+#include <iterator>
+#include <span>
+#include <string>
+#include <utility>
+#include <vector>
+
 constexpr uint8_t DB_TXINDEX{'t'};
 
 std::unique_ptr<TxIndex> g_txindex;
diff --git a/src/index/txindex.h b/src/index/txindex.h
index f8236c92..889b6612 100644
--- a/src/index/txindex.h
+++ b/src/index/txindex.h
@@ -6,6 +6,15 @@
 #define BITCOIN_INDEX_TXINDEX_H
 
 #include <index/base.h>
+#include <primitives/transaction.h>
+
+#include <cstddef>
+#include <memory>
+
+class uint256;
+namespace interfaces {
+class Chain;
+}
 
 static constexpr bool DEFAULT_TXINDEX{false};