fix(e2e): wait for fresh runners endpoint

[casey-brooks]

Summary

• Fix runners source-deploy readiness so E2E waits for a fresh source pod ready marker instead of stale logs.
• Wait for synced migration files before go run, preventing the observed missing github.com/agynio/runners/migrations package crash.
• Wait for ready service endpoints before starting E2E and add failure diagnostics for pods, service/endpoints, logs, describes, and /tmp/runners-devspace.log.

Follow-up to #59 after it was merged.

Test & lint summary

• buf generate buf.build/agynio/api --include-imports --path agynio/api/agents/v1 --path agynio/api/runner/v1 --path agynio/api/runners/v1 --path agynio/api/identity/v1 --path agynio/api/authorization/v1 --path agynio/api/ziti_management/v1 --path agynio/api/notifications/v1: completed successfully
• go test ./...: passed 1 / failed 0 / skipped 0
• go vet ./...: passed with no errors
• devspace run-pipeline --help: passed config load and listed diagnostics-runners

[casey-brooks]

Root cause and fix details

I inspected E2E run 26501969016 artifacts/logs. /tmp/runners-devspace.log was not included in the downloaded artifact, but the uploaded suite diagnostics contained enough runner pod logs to identify the cause.

Concrete cause: wait-runners matched a stale runners: ready log from the pre-existing deployed image and returned immediately. E2E then started while the DevSpace source pod was not serving. The source pod later crashed before listening with:

internal/db/migrate.go:9:2: no required module provides package github.com/agynio/runners/migrations

That happened because the source-sync wait only checked for go.mod, buf files, and cmd/runners/main.go; go run could start before the embedded migrations package was synced.

This PR fixes that deterministically by requiring a fresh per-run ready marker, waiting for migration files before go run, and waiting for ready service endpoints before E2E starts. It also adds failure diagnostics for pods, service/endpoints, endpoint slices, current/previous logs, pod describes, and /tmp/runners-devspace.log.

Test & lint summary

• buf generate buf.build/agynio/api --include-imports --path agynio/api/agents/v1 --path agynio/api/runner/v1 --path agynio/api/runners/v1 --path agynio/api/identity/v1 --path agynio/api/authorization/v1 --path agynio/api/ziti_management/v1 --path agynio/api/notifications/v1: completed successfully
• go test ./...: passed 1 / failed 0 / skipped 0
• go vet ./...: passed with no errors
• devspace run-pipeline --help: passed config load and listed diagnostics-runners