feat: perf improvements for build_pending_state

[haardikk21]

Attempts to improve the performance of processing flashblocks when flashblocks are coming in faster than canonical blocks. Forces a reset of the CacheDB periodically when pending max depth > 3. This helps keep things more stable and avoids cases where processing flashblocks takes more time than it takes for a new flashblock to come in, which ends up causing a pending head stall as latest starts outpacing pending.

Also improves sender recovery and receipt generation by caching those as much as possible

[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

Approved review 3465230484 from danyalprout is now dismissed due to new commit. Re-request for approval.