Allow LSQ clients to connect during initial LedgerDB replay (EarlyN2C)
Allow the local node-to-client socket to bind within seconds of node startup rather than after the multi-hour LedgerDB replay completes. n2c ChainSync clients (cardano-db-sync, ogmios, wallet) can begin streaming blocks during replay; LSQ / TxSubmit / TxMonitor handlers naturally block on the LedgerDB until ready, relying on the property that NtC has no client-side timeouts. Phase 1 (ChainDB): - New 'LedgerDBStatus' type + 'awaitLedgerDB' STM helper - 'openDBInternal' returns once Immutable+Volatile are open; LedgerDB replay and initial chain selection run on a registry-linked background thread (new 'runInitLedgerDB') - LedgerDB-touching queries wrapped in 'awaitLedgerDB' - New 'OpenedDBImmutableReady' trace event; existing 'OpenedDB' preserved - 'closeDB' cancels the background initialiser and only closes the LedgerDB if 'cdbLedgerDBStatus' has reached 'LdbReady' Phase 2 (NodeKernel + runWith): - 'mkPendingMempool', 'mkPendingBlockchainTime', 'mkPendingDurationUntilTooOld' forwarding wrappers that block on a TMVar until populated - 'initInternalState' split into 'initInternalStateEarly' + 'completeInternalState' - 'initNodeKernel' split into 'initNodeKernelEarly' returning '(NodeKernel, m ())'; the deferred action opens the real mempool, computes the real GsmState, and spawns the four ledger-touching background threads (GSM, GDD watcher, blockForging, blockFetchLogic, decisionLogicThreads) - 'runWith' allocates the BlockchainTime / WrapDurationUntilTooOld TMVars, builds the kernel synchronously with pending wrappers, calls 'llrnRunDataDiffusion' immediately, and forks a 'Node.lateInit' thread that runs 'hardForkBlockchainTime' and 'realDurationUntilTooOld' once the LedgerDB is ready, populates the TMVars, and runs the completer Verified: 'cabal build all' clean and 'cabal test storage-test' passes 69/69 on the 3.0.1.0 release tag.
