Flakey tests

[joshuasing]

This issue is to track flakey tests across the repository.

[joshuasing]

https://github.com/hemilabs/heminetwork/actions/runs/18662839755/job/53207190555?pr=717

--- FAIL: TestNotFoundError (0.05s)
    --- FAIL: TestNotFoundError/BlockKeystoneByL2KeystoneAbrevHash (0.00s)
panic: runtime error: index out of range [0] with length 0 [recovered, repanicked]

FAIL	github.com/hemilabs/heminetwork/v2/service/tbc	136.241s

[joshuasing]

https://github.com/hemilabs/heminetwork/actions/runs/18662839755/job/53207190555?pr=717#step:5:39425

--- FAIL: TestDisconnectedOpgeth (45.00s)
2025-10-20 19:37:16 TRACE popm popm.go:661 opgeth exit
2025-10-20 19:37:16 INFO popm popm.go:993 pop miner has shutdown cleanly

panic: context deadline exceeded

FAIL	github.com/hemilabs/heminetwork/v2/service/popm	47.819s

---

Another occurrence: https://github.com/hemilabs/heminetwork/actions/runs/18662804587/job/53207080702?pr=715#step:5:1013

panic: context deadline exceeded

goroutine 240 [running]:
github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth.func1()
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:337 +0x65
created by github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth in goroutine 237
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:335 +0x5d2
FAIL	github.com/hemilabs/heminetwork/v2/service/popm	47.560s

---

Another: https://github.com/hemilabs/heminetwork/actions/runs/18660859115/job/53200775057?pr=710#step:5:1027

panic: context deadline exceeded

goroutine 267 [running]:
github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth.func1()
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:337 +0x65
created by github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth in goroutine 264
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:335 +0x5d2
FAIL	github.com/hemilabs/heminetwork/v2/service/popm	47.570s

---

Another: https://github.com/hemilabs/heminetwork/actions/runs/18660863727/job/53200790200?pr=712#step:5:1011

panic: context deadline exceeded

goroutine 261 [running]:
github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth.func1()
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:337 +0x65
created by github.com/hemilabs/heminetwork/v2/service/popm.TestDisconnectedOpgeth in goroutine 258
	/home/runner/work/heminetwork/heminetwork/service/popm/popm_test.go:335 +0x5d2
FAIL	github.com/hemilabs/heminetwork/v2/service/popm	47.585s