revert(001): drop Serialized from aggregator-head-lag

[Flotapponnier]

Reverts #2268 before it reaches main. Nothing to retract publicly: the three Railway head-lag services build from main, so Serialized never collected a sample in production.

What was measured (2026-09-08)

One WS connection, the four bench pools, 240 s capture, plus a 150 s run asking a public Base node whether the block existed at the moment each trade arrived. Single vantage, NTP offset +0.078 s.

The ruler matches. Their at is the block timestamp exactly, so head_lag_seconds would measure the same quantity as Mobula's trade.Date and Codex's event.Timestamp.

chain	n	median(at − block timestamp)
base	105	+0.000 s
bnb	1	+0.000 s
solana	28	+0.473 s (getBlockTime returns whole seconds)

But they read a different thing.

check	result
median(receipt − block timestamp), base	−0.911 s
base events with negative lag	105/105
trades received before the block existed on a node	11/11
median lead over block publication	1.04 s

In all eleven cases the node head at receipt was exactly target block − 1. The block was not late in propagation, it did not exist yet. The spread (−0.21 s to −1.80 s) is one Base slot.

Why revert rather than ship

Serialized streams sequencer preconfirmations; Mobula, Codex and GeckoTerminal read sealed blocks. A preconfirmation carries no finality guarantee and can be reordered, so the ~1.5 s lead is a latency/finality trade-off, not a speed gap. One ranking would present it as superiority.

Mechanically it also breaks: RecordHeadLag drops lagSeconds < 0, so on Base they would read as no data while being the fastest, and any rare positive sample would stick on the gauge and become their published p50.

Open with them

• preconfirmed was false on all eleven events that preceded block publication. A consumer cannot tell the two regimes apart from the payload.
• Robinhood delivered 0 events in 240 s despite an acknowledged subscription, against 79 in 90 s on 2026-09-06.

Reopen if

The bench gains an emission-regime dimension (sealed vs preconfirmed), or a landing-rate companion series shows their preconfirmations reach sealed blocks 1:1.

Serialized stays on benches 004, 005, 008 and 090, where the comparison is like for like. Audit §18.1 records all of the above. 218 specs valid, harness builds.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LtBjM1FhTKxiZhwzb3Y61c