GFQL monolith shrinkdown S5: add CI growth guards for lowering/CompiledCypher surfaces

[lmeyerov]

Summary

Execution slice S5 under #1260.

Add/refresh CI metrics and guardrails so monolith shrinkdown gains are measurable and do not regress.

Scope

In scope:

• Add a lightweight metric/report step for lowering.py LOC trend
• Track CompiledCypher* dataclass field/property counts
• Add no-growth or bounded-growth gate policy for the tracked surfaces
• Document thresholds and update path when intentional growth is required

Out of scope:

• Large refactors unrelated to measurement/guardrails
• Runtime/planner semantic changes

Acceptance

1. CI emits clear metrics for lowering.py size and CompiledCypher* surface counts.
2. Guardrail fails on unapproved growth per defined thresholds.
3. Developer docs include how to refresh baselines when intentionally needed.
4. Existing CI matrix remains stable.

Related

• Parent: Meta: GFQL monolith shrinkdown (lowering.py + CompiledCypher cleanup) #1260
• Prior slices: GFQL monolith shrinkdown S1: retire dual-contract reentry extras path #1294 GFQL monolith shrinkdown S2: extract bounded reentry glue from lowering.py #1295 GFQL monolith shrinkdown S3: split lowering.py by concern boundaries #1301 GFQL monolith shrinkdown S4: reduce CompiledCypher compatibility surface #1305
• Meta queue: Meta: benchmark coverage unlock plan for GFQL and GFQL/Cypher #992

[lmeyerov]

Landed via PR #1310 and merged to master on 2026-05-05 (merge SHA efc3bb042f762ec5ab3fdd0ed5495cd7da023b58).

S5 acceptance receipts:

• CI emits explicit metrics for:
  • graphistry/compute/gfql/cypher/lowering.py total LOC
  • CompiledCypherQuery / CompiledGraphBinding / CompiledCypherGraphQuery dataclass field + @property counts
• Added growth guard with baseline policy:
  • script: bin/ci_cypher_surface_guard.py
  • baseline: bin/ci_cypher_surface_guard_baseline.json
  • CI job: cypher-frontend-surface-guard
  • chained into: cypher-frontend-ci-gates
• Developer refresh path documented in DEVELOP.md (python bin/ci_cypher_surface_guard.py --write-baseline)
• CI matrix remained stable and fully green on S5: add CI growth guards for lowering/CompiledCypher surfaces (#1306) #1310 (including TCK/docs/full fanout lanes)
• Review flow converged in 3 waves with zero findings (plans/1306-s5-ci-growth-guards/final-report.md)

Parent tracking: #1260 (S5)