exp 169: guard Tracelite workload insights

[danReynolds]

Hypothesis

Adding a Resqlite-side validation step after tracelite explain turns exp 143's manual workload-summary interpretation into an artifact contract. The profile wrapper should fail if canonical Tracelite profile insights regress to coverage-only output.

Approach

• Validate insights.json after benchmark/profile/run_tracelite_profile.dart runs explain tracelite workload summary.
• Require stable workload-summary insight IDs: dispatch floors, work-bound operations, tail spread, RSS movement, allocation counters, and WAL movement.
• Add fixture tests for a complete insights artifact and a thin workload_loaded-only artifact.
• Record exp 169, compact aggregate results, README row, signal-map update, and regenerated experiment history.

Results

Signal	Result
Real profile guard	validated workload-summary insights: 8 ids
Noop floors	reader 8 us, writer 11 us
Dispatch-bound insight	point_query/select 0 us work over 8 us median
Work-bound insight	merge_rounds/executeBatch 69 us work over 80 us median
Memory/allocation	point_query RSS +22.110 MB, 50,000 rows / 300,000 cells decoded
WAL signal	single_insert +1,713,920 B; merge_rounds +8,240 B

Outcome

In Review - measurement-system guardrail. Exp 143's Tracelite interpretation follow-up is consumed for the Resqlite profile workflow; this does not change runtime behavior.

Test plan

• dart pub get
• dart test test/tracelite_profile_workflow_test.dart
• dart run benchmark/profile/run_tracelite_profile.dart --tracelite-root=/Users/dan/Coding/tracelite --tracelite-revision=11159638962f5176678f02551a78180f5b9d3bba --label=exp-169-tracelite-workload-insights --out-dir=build/tracelite-profile/exp-169-tracelite-workload-insights --no-graph-data
• dart run benchmark/finalize_experiment.dart --experiment=experiments/169-tracelite-workload-insights.md
• dart analyze benchmark/profile/run_tracelite_profile.dart test/tracelite_profile_workflow_test.dart
• git diff --check
• jq empty experiments/signals.json docs/experiments/history.json