fix(basectl): Silent Panics

[refcell]

Summary

basectl would silently stop updating after running for a while. Investigation
found that when the flashblock WebSocket connection dropped (network hiccup,
server restart, timeout), the task would exit and never reconnect. The UI
kept running but no new data flowed in.

Changes:

• WebSocket functions now loop forever, reconnecting on any failure
• Exponential backoff: 1s -> 2s -> 4s -> ... -> 30s max between retries
• Backoff resets on successful connection
• Malformed messages are skipped instead of crashing the task
• Tasks only exit when the channel closes (app shutdown)

Also fixes DA backlog calculation to use full encoded transaction size
instead of just calldata, matching how flashblocks calculate DA bytes.

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 1/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1