Update dependencies and refresh model pricing for 2026-05

[mattgodbolt-molty]

Summary

• Bump all runtime and dev dependencies to current latest (notably anthropic 0.83 → 0.100, fastapi 0.129 → 0.136, pydantic 2.12 → 2.13, starlette 0.52 → 1.0, boto3 1.42 → 1.43).
• Refresh MODEL_FAMILIES against the current Anthropic price list (pricing docs):
  • Add Opus 4.7 at the new $5/$25 tier (also 1M context).
  • Move Opus 4.5 and Opus 4.6 to the same $5/$25 tier — previously priced at the old $15/$75.
  • Drop retired families (Opus 3, Haiku 3, Sonnet 3.5, Sonnet 3.7) from the price table. The regex normaliser still parses their names so callers get an explicit "not found" error rather than a stale price.
• Update tests to cover the new Opus 4.6/4.7 pricing and to assert that retired families are explicitly rejected.

Anthropic still does not publish a programmatic pricing endpoint, so the table remains hand-maintained. The /v1/models endpoint exposes capabilities and display names but no prices; if we ever want to automate this, LiteLLM's model_prices_and_context_window_backup.json is the most actively-maintained third-party source.

Test plan

• uv run pytest (92 tests pass)
• uv run pre-commit run --all-files
• Smoke-test against the live API with ./test-explain.sh after merge

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Updates the project’s Python dependencies and refreshes Anthropic Claude model pricing metadata to match the current published price tiers, with corresponding test updates to validate the new pricing and retired-model behavior.

Changes:

• Bumped runtime/dev dependencies in pyproject.toml to newer versions (notably Anthropic SDK and FastAPI stack).
• Updated MODEL_FAMILIES pricing (Opus 4.5+ moved to $5/$25 tier; added Opus 4.7; removed retired families).
• Updated tests to validate new Opus/Sonnet pricing and ensure retired families raise explicit “not found” errors.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 3 comments.

File	Description
pyproject.toml	Updates dependency minimum versions for runtime and dev tooling.
app/model_costs.py	Refreshes the hand-maintained Claude model family pricing table and related notes.
app/test_model_costs.py	Updates/extends tests to cover new pricing tiers and retired model family rejection.

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[Copilot]

This retired-model test omits Sonnet 3.7 even though the pricing table removes it and the normalizer still parses it. Add an assertion that looking up a Sonnet 3.7 model name raises the same “not found” error to fully cover the retired-family behavior.