feat: implement issue #1896 — [Phase 1] Price claude-opus-5-5 in model-pricing.tsv and lock it with a regression test
Problem
[Phase 1] Price claude-opus-5-5 in model-pricing.tsv and lock it with a regression test
From the issue: As a cost-observability maintainer, I want add a date-versioned claude-opus-5-5 pricing row and a regression test that pins its rate, so that deep-tier token-cost reports price Opus 5.5 calls correctly the moment the model is invoked, instead of falling through to no matching glob.
Risk
Low — changes automation shell logic under scripts/, covered by shellcheck (--severity=warning) and the bats suite.
Test plan
Tests added/updated: tests/model_pricing.bats. Verification: bash scripts/dev-lead-lint.sh (shellcheck --severity=warning) ran pre-commit; the bats suite runs in CI.
Rollback
Revert this PR. No non-revertible side effects (no tags, migrations, or external state).
Monitoring
This PR's Lint (shellcheck) and bats checks show pass/fail; watch subsequent dev-lead / pr-review runs for behavioral regressions.
Closes #1896