feat: support pox-5

[brady-stacks]

• Add PoX-5 support to Clarinet (pox-5 boot contract, epoch 3.5 config, updated stacking/signing logic for new PoX
• devnet snapshot uses a SnapshotLevel enum now (epoch 3.5 burn height 163)
• Update default epoch timing constants (3.1–3.5) so epochs transition at consecutive burn heights, and make epoch 3.5 a non-optional default in DevnetConfig
• Add btc_balance field to AccountConfig for seeding BTC in stacker wallets during devnet genesis
• Add PoX-5 stacking transaction generation using make_pox_5_signer_key_signature / make_pox_5_signer_grant_signature
• Handle snapshot boot gaps in the observer's StacksBlockPool by creating a new fork when a block is far ahead (>10 blocks) of all existing fork tips
  • Skip Docker image pull when the image already exists locally
  • Skip devnet compatibility checks when --from-genesis is passed

[codecov]

Codecov Report

❌ Patch coverage is 11.31824% with 666 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...omponents/stacks-network/src/chains_coordinator.rs	10.11%	551 Missing ⚠️
components/stacks-network/src/orchestrator.rs	0.00%	71 Missing ⚠️
components/stacks-network/src/lib.rs	0.00%	18 Missing ⚠️
...ponents/observer/src/indexer/stacks/blocks_pool.rs	35.71%	9 Missing ⚠️
components/clarinet-cli/src/frontend/cli.rs	0.00%	8 Missing ⚠️
components/clarity-repl/src/repl/datastore.rs	20.00%	4 Missing ⚠️
components/clarinet-deployments/src/types.rs	33.33%	2 Missing ⚠️
components/clarinet-files/src/network_manifest.rs	85.71%	1 Missing ⚠️
components/clarity-repl/src/repl/mod.rs	50.00%	1 Missing ⚠️
...omponents/stacks-network/src/snapshot_extractor.rs	0.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[hugo-stacks]

We don't want to have a default value here.

At some point, we'll be in a state where Clarinet will have to support both epoch 3.4 (by default) and preview for epoch 3.5.

If/when the user sets an epoch 3.5 height (along with a 3.5 image), Clarinet will handle it, but otherwise it'll still default to 3.4 until 3.5 activates on mainnet.

Until will eventually default to 3.5, like we recently did for 3.4 #2342