chore(deps): move onto cometbft bera-v0.39.x re-fork

[fridrik01]

This PR updates beacon-kit to move off the bera-v1.x cometbft line onto the bera-v0.39.x re-fork (berachain/cometbft#51). The v0.39 line drops the v1 api module and ABCI surface, so cosmos-sdk moves with it to v0.54 and store/v2 (the old cosmossdk.io/store relocated upstream, same IAVL disk format).

Most of the diff is mechanical renames and import moves. The substantive bits are stubs for the new mempool ABCI methods and a local replacement for the sdk validator-file helpers, which lost BLS key-type selection.

One behavior change, v0.39 has no SyncingToHeight, so the DA-window check and node-api sync status use the finalized height instead. We may want to restore that field in the fork.

[codecov]

Codecov Report

❌ Patch coverage is 44.23077% with 87 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.04%. Comparing base (59c0fd1) to head (4d2020c).

Files with missing lines	Patch %	Lines
cli/utils/privval/privval.go	46.66%	17 Missing and 7 partials ⚠️
consensus/cometbft/service/abci.go	25.80%	23 Missing ⚠️
consensus/cometbft/service/service.go	27.77%	13 Missing ⚠️
consensus/cometbft/service/log/sdk_logger.go	0.00%	8 Missing ⚠️
consensus/cometbft/cli/commands.go	0.00%	6 Missing ⚠️
consensus/cometbft/service/abci_utils.go	0.00%	4 Missing ⚠️
storage/deposit/common/synced_db.go	0.00%	4 Missing ⚠️
beacon/blockchain/finalize_block.go	0.00%	0 Missing and 1 partial ⚠️
cli/commands/deposit/db_check.go	0.00%	1 Missing ⚠️
cli/commands/root.go	0.00%	1 Missing ⚠️
... and 2 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3155      +/-   ##
==========================================
- Coverage   63.10%   63.04%   -0.07%     
==========================================
  Files         372      372              
  Lines       15549    15580      +31     
==========================================
+ Hits         9812     9822      +10     
- Misses       4777     4794      +17     
- Partials      960      964       +4     

Files with missing lines	Coverage Δ
beacon/blockchain/process_proposal.go	68.96% <ø> (ø)
cli/commands/genesis/deposit.go	44.21% <100.00%> (ø)
cli/commands/initialize/initialize.go	56.43% <100.00%> (ø)
cli/commands/server/pruning.go	27.77% <ø> (ø)
cli/commands/server/start.go	0.00% <ø> (ø)
config/config/config.go	0.00% <ø> (ø)
consensus/cometbft/service/cache/state.go	87.50% <ø> (ø)
consensus/cometbft/service/commit.go	52.17% <100.00%> (ø)
consensus/cometbft/service/configs.go	52.43% <100.00%> (ø)
consensus/cometbft/service/delay/config.go	64.70% <ø> (ø)
... and 24 more

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