Main pre-commit broken: gocyclo complexity 12 in recEffectiveSavingsPct #1222

The pre-commit workflow's gocyclo hook fails on current main:

12 config recEffectiveSavingsPct internal/config/store_postgres_recommendations.go:320:1

recEffectiveSavingsPct was introduced by PR #1206 (merged as cfead3b) with cyclomatic complexity 12, above the hook's -over 10 threshold. The hook runs gocyclo -over 10 over all non-test Go files, so every PR's "Run pre-commit hooks" CI job now fails regardless of what the PR touches (observed on PR #1219, and reproducible locally with gocyclo -over 10 internal/config/store_postgres_recommendations.go on main).

PR #1220 (fix/main-ci-failing-jobs) fixed the lint, govulncheck, and test failures on main but did not address this one.

Fix: refactor recEffectiveSavingsPct to complexity <= 10, for example by extracting the on-demand baseline reconstruction into a helper. Behavior must stay identical (the function's semantics are covered by the #1103/#1148 net-savings rules documented in its comment).