cbt: address devnet CBT instances by their analytics ingress host

[samcm]

panda cbt 404s for every devnet: the module derives https://cbt.<network>.ethpandaops.io for all networks, but devnets have no such DNS record — the per-devnet wildcard resolves to the devnet fleet's own ingress, not the analytics cluster hosting CBT. Devnet CBT instances are already reachable at <network>-xatu-cbt.analytics.production.platform.ethpandaops.io (provisioned per devnet by the mca-devnets ApplicationSet, derived from the network name alone), so NetworkBaseURL now routes *-devnet-* networks there. Named networks keep the vanity host.

[github-actions]

🐼 Smoke eval — bded9a1: ✅ 8/8 pass

📊 Interactive report — tokens p50 16,814 · tokens/solve 21,761.

Reference points: master@4e689dd 100% · v0.38.5 98%.

question	result	tokens	tools
forky_node_coverage	✅	14,552	4
tracoor_node_coverage	✅	16,253	5
mainnet_block_arrival_p50	✅	15,075	6
list_datasources	✅	13,001	2
block_count_24h	✅	24,210	10
missed_slots_24h	✅	25,700	13
chartkit_default_arrival_distribution	✅	47,920	24
storage_upload_session_scoped	✅	17,376	9

🔭 Langfuse traces (8 runs; ⚠️ = failed)

• forky_node_coverage
• tracoor_node_coverage
• mainnet_block_arrival_p50
• list_datasources
• block_count_24h
• missed_slots_24h
• chartkit_default_arrival_distribution
• storage_upload_session_scoped

_{The report walks this branch's commits against the master baseline and the most recent release. A self-contained copy is in the run's eval-smoke-* artifact.}