feat(cost,budgets): impute token cost for subscription runs and enforce it - #11104

Scanned 9 changed files across CI/CD, lifecycle, and malicious-intent dimensions. No GitHub Actions workflow files were modified. No package-manager lifecycle hooks, build scripts, or startup entrypoints were touched. The changes implement a cost-imputation feature (effective_cents budget metric) for subscription runs using a static model-pricing table and drizzle-orm parameterized SQL. No secret exfiltration, obfuscation, encoded payloads, network calls, dependency changes, eval/exec, or hidden-behavior patterns were found.