feat(o11y): self-logs via shared entry-point zap->OTel bridge + OTLP log export (PIPE-1066)

[Dylan-M]

Proposed Change

Bridges blitz's own zap logging into an OTel LoggerProvider so internal logs export as
OTLP records, opt-in through telemetry.logs. The logger is bridged once at each process
entry point (main for standalone; config.LoadModules and the embed runner for embed),
and shared from there. A bridged zap logger propagates to the child loggers components
derive, so components do not re-bridge. Also collapses the host's flat provider fields
into the single Host.Telemetry bundle, so one value carries all three signals.

Each setting is exposed on all three config surfaces, like every other blitz option: the
telemetry.logs config block, BLITZ_TELEMETRY_LOGS_* env vars, and --telemetry-logs-*
flags.

How to validate

• Point blitz at any OTLP gRPC collector (its debug exporter shows the log records). Run:
  go run ./cmd/blitz --generator-type apache-common --generator-apache-common-rate 1s --output-type stdout --telemetry-logs-otlpendpoint localhost:4317 --telemetry-logs-insecure
• Confirm blitz's own startup and generator log lines arrive at the collector as OTLP
  records. They still print to stdout too.
• Drop the two --telemetry-logs-* flags and confirm logging stays stdout-only.
• go test ./embed/ runs TestEmbed_HostBundleReceivesAllThreeSelfSignals, which asserts
  one host bundle receives metrics, spans, and bridged logs together.
• go test ./internal/config/... covers the flag, env, and default for each new setting.

Checklist

• Changes are tested
• CI has passed

[Dylan-M]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• fix(o11y): record output request + HEC ACK-poll latency in ms (PIPE-1404) #292
• feat(o11y): lifecycle startup-latency metrics via new runtime weaver registry (PIPE-1066) #291
• feat(o11y): bring stdout/nop outputs fully into the self-telemetry spine (PIPE-1066) #290
• feat(o11y): per-batch output send spans + HEC ACK-poll span (PIPE-1066) #289
• feat(o11y): wire fix generator into the self-telemetry spine (PIPE-1066) #288
• feat(o11y): self-logs via shared entry-point zap->OTel bridge + OTLP log export (PIPE-1066) #287 👈 (View in Graphite)
• feat(o11y): self-tracing via runtime spans, adapter emit spans, and OTLP trace export (PIPE-1066) #286
• feat(o11y): per-instance metrics via injectable MeterProvider, drop package globals (PIPE-1066) #285
• feat(embed): add TelemetrySettings provider bundle + NopTelemetry (PIPE-1066) #284
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.