fastapi-fix

Fix all lint, format, and type errors in the current changes. ## Steps 1. **Read CLAUDE.md** to find the project's lint, format, and type-check commands. If they're missing, fall back to the stack defaults below. 2. **Read any `.claude/rules/*.md`** whose `paths:` glob matches the files you're about to touch — they may carry style/typing rules the linter doesn't enforce. 3. **Scope to this branch's change.** Build the changed-file list — the union of: - `git diff --name-only master...HEAD` (work committed on this branch) - `git diff --name-only` (unstaged) and `git diff --name-only --cached` (staged) Pass these paths to every command below so the tools judge only what this branch changed — never the whole repo. Pre-existing violations in untouched files are not yours to fix here. If the list is empty, there's nothing to fix; say so and stop. (If `master...HEAD` errors because the base branch isn't present locally, fall back to the uncommitted diff alone.) 4. **Run each command in this order, scoped to the changed files** (apply each pass before running the next, so fixes from one don't fight the next): 1. **Format** first (it normalizes whitespace and quoting that lint rules might complain about). 2. **Lint** next (it picks up real style/safety issues on top of formatted code). 3. **Type-check** last (type errors don't move under format/lint, but the line numbers will). If the type-checker needs whole-project context to resolve imports, run it normally bu...