Merge #6742: refactor: move InstantSend impl. to src/instantsend/ and split sources for islock, database and masternode logic out of manager source

6360725 chore: resolve incomplete/missing copyright headers in unit tests (Kittywhiskers Van Gogh)
d1de786 chore: cleanup unused headers from instantsend (dependent) sources (Kittywhiskers Van Gogh)
b4d1bd2 refactor: `llmq::CInstantSendLock{,Ptr}` > `instantsend::InstantSendLock{,Ptr}` (Kittywhiskers Van Gogh)
8d78e7d refactor: remove need for mutual access to private members (Kittywhiskers Van Gogh)
f22fb22 refactor: separate masternode mode logic into dedicated manager class (Kittywhiskers Van Gogh)
544791d refactor: move masternode mode logic to `instantsend/signer.{cpp,h}` (Kittywhiskers Van Gogh)
82dded4 refactor: move `CInstantSendDb` definition to `instantsend/db.{cpp,h}` (Kittywhiskers Van Gogh)
5e70456 refactor: move `CInstantSendLock` definition to `instantsend/lock.{cpp,h}` (Kittywhiskers Van Gogh)
ac8dcdd refactor: move `CInstantSendManager` constructor to source file (Kittywhiskers Van Gogh)
9edd27b refactor: `llmq/instantsend.{cpp,h}` > `instantsend/instantsend.{cpp,h}` (Kittywhiskers Van Gogh)

Pull request description:

  ## Motivation

  Currently, the `llmq` namespace includes the LLMQ subsystem itself and capabilities built on them, primarily InstantSend and ChainLocks. Both capabilities play a key part in block and validation logic (see `CChainHelper` passthrough functions, [source](https://github.com/dashpay/dash/blob/9310ebc43cdc4ccde7b3033f4d18139258d7c7ad/src/evo/chainhelper.cpp#L28-L60)). Currently, we have to setup all LLMQ infrastructure (i.e. `LLMQContext`) in order to validate on-disk information.

  This ceases to be feasible when extracting validation code that interacts with on-disk state into `libbitcoinkernel` through `bitcoin-chainstate` (see [bitcoin#24304](bitcoin#24304)) as this thinned down library is devoid of networking capabilities.

  As LLMQ is inherently an interactive system that is tied to networking capabilities, to extract on-disk state validation logic, we need to separate out networking from non-networking concerns. This pull request is the first step in extracting networking logic by first splitting out the monolithic InstantSend implementation into smaller concerns and then spinning off masternode-mode logic into a dedicated manager.

  Future work should aim to spit out non-masternode networking code into a separate concern and eventually thin down `llmq::CInstantSendManager` to be capable of running with a networking-disabled mode, which would be adequate for `libbitcoinkernel`.

  ## Breaking Changes

  None expected.

  ## Checklist

  - [x] I have performed a self-review of my own code
  - [x] I have commented my code, particularly in hard-to-understand areas **(note: N/A)**
  - [x] I have added or updated relevant unit/integration/functional/e2e tests
  - [x] I have made corresponding changes to the documentation **(note: N/A)**
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  UdjinM6:
    utACK 6360725

Tree-SHA512: 174532789cc390d0c027016a5f72b4fe1979ac10597d8bfc50e2f8edb739cc26c1fd298f2ecc82b048026c8b8e560083dbae41105e8dcde57bb8d92df0621ca1

Author: PastaPastaPasta

src/Makefile.am

@@ -230,6 +230,10 @@ BITCOIN_CORE_H = \
   interfaces/ipc.h \
   interfaces/node.h \
   interfaces/wallet.h \
+  instantsend/db.h \
+  instantsend/instantsend.h \
+  instantsend/lock.h \
+  instantsend/signing.h \
   key.h \
   key_io.h \
   limitedmap.h \
@@ -243,7 +247,6 @@ BITCOIN_CORE_H = \
   llmq/dkgsessionhandler.h \
   llmq/dkgsessionmgr.h \
   llmq/ehf_signals.h \
-  llmq/instantsend.h \
   llmq/options.h \
   llmq/params.h \
   llmq/quorums.h \
@@ -488,6 +491,10 @@ libbitcoin_node_a_SOURCES = \
   index/coinstatsindex.cpp \
   index/txindex.cpp \
   init.cpp \
+  instantsend/db.cpp \
+  instantsend/instantsend.cpp \
+  instantsend/lock.cpp \
+  instantsend/signing.cpp \
   llmq/blockprocessor.cpp \
   llmq/chainlocks.cpp \
   llmq/clsig.cpp \
@@ -498,7 +505,6 @@ libbitcoin_node_a_SOURCES = \
   llmq/dkgsessionhandler.cpp \
   llmq/dkgsessionmgr.cpp \
   llmq/ehf_signals.cpp \
-  llmq/instantsend.cpp \
   llmq/options.cpp \
   llmq/quorums.cpp \
   llmq/signing.cpp \

src/bench/rpc_blockchain.cpp

@@ -6,9 +6,9 @@
 #include <bench/data.h>
 
 #include <consensus/validation.h>
+#include <instantsend/instantsend.h>
 #include <llmq/chainlocks.h>
 #include <llmq/context.h>
-#include <llmq/instantsend.h>
 #include <rpc/blockchain.h>
 #include <streams.h>
 #include <test/util/setup_common.h>

src/coinjoin/coinjoin.cpp

@@ -9,8 +9,8 @@
 #include <chainparams.h>
 #include <consensus/validation.h>
 #include <governance/common.h>
+#include <instantsend/instantsend.h>
 #include <llmq/chainlocks.h>
-#include <llmq/instantsend.h>
 #include <masternode/node.h>
 #include <masternode/sync.h>
 #include <messagesigner.h>

src/dsnotificationinterface.cpp

@@ -16,12 +16,11 @@
 
 #include <evo/deterministicmns.h>
 #include <evo/mnauth.h>
-
+#include <instantsend/instantsend.h>
 #include <llmq/chainlocks.h>
 #include <llmq/context.h>
 #include <llmq/dkgsessionmgr.h>
 #include <llmq/ehf_signals.h>
-#include <llmq/instantsend.h>
 #include <llmq/quorums.h>
 
 CDSNotificationInterface::CDSNotificationInterface(CConnman& connman,

src/evo/chainhelper.cpp

@@ -6,8 +6,9 @@
 
 #include <consensus/params.h>
 #include <evo/specialtxman.h>
+#include <instantsend/instantsend.h>
+#include <instantsend/lock.h>
 #include <llmq/chainlocks.h>
-#include <llmq/instantsend.h>
 #include <masternode/payments.h>
 
 CChainstateHelper::CChainstateHelper(CCreditPoolManager& cpoolman, CDeterministicMNManager& dmnman,

src/init.cpp

@@ -87,11 +87,11 @@
 #include <evo/mnhftx.h>
 #include <flat-database.h>
 #include <governance/governance.h>
+#include <instantsend/instantsend.h>
 #include <llmq/context.h>
 #include <llmq/dkgsessionmgr.h>
 #include <llmq/options.h>
 #include <llmq/signing.h>
-#include <llmq/instantsend.h>
 #include <masternode/meta.h>
 #include <masternode/node.h>
 #include <masternode/sync.h>