v3.2.0 — Typed HTTP retry exceptions

Added

• RateLimitedError, ServiceUnavailableError, and NetworkError exception classes for typed handling of HTTP 429, 503, and transport-level failures. All three preserve existing except catch sites via inheritance.
• max-inline-sleep retry-policy key (default 300 s), configurable via custom_retry_policy; a 503 whose Retry-After exceeds the cap raises instead of sleeping inline.

Changed

• HTTP 429 raises RateLimitedError immediately instead of falling through as a raw HTTPError.
• urllib.error.URLError is caught and re-raised as NetworkError.
• Replace e.hdrs with e.headers in retrieveFromUrlWaiting().
• Chain re-raised exceptions with raise ... from in client.py, server.py, and datestamp.py so tracebacks show the original cause (Ruff B904 / PEP 3134).
• Build the published wheel inside the project's Nix flake devShell (publish.yml). Pure-Python source semantics unchanged; published artifact bytes may differ across releases due to build-toolchain provenance.
• Development tooling and CI infrastructure improvements:
  • lint: Add Ruff as the Python lint and format gate via pre-commit (#18)
  • style: Repo-wide ruff format pass (#20)
  • chore: pre-commit hook for flake.lock drift detection (#25)
  • ci: Nix flake devShells for CI and publish workflows (#22)
  • ci: Centralise Nix-store and uv-wheel caches via composite Actions (#24)
  • refactor: Split flake.nix into flake-parts modules; nixfmt-rfc-style formatting and treefmt hook (#31)

Deprecated

• Passing 429 or 503 in a caller-supplied expected-errcodes set now emits DeprecationWarning; catch the typed exceptions instead.