v0.5.1

[0.5.1] - 2026-05-17

Documentation-only patch on top of 0.5.0.

Added

• ## Tool-call handling section in the README describing what
  erllama exposes (per-model tool_call_markers, the
  {tool_call_delta, _} / {erllama_tool_call_end, _, Full}
  streaming wire, and the automatic greedy-on-syntax sampler
  swap) and what it deliberately leaves to the HTTP layer (tool
  id minting, JSON parsing, canonicalisation).
• New guides/tool-calls.md companion to the README section,
  linked from the documentation table.
• New internals/request-lifecycle.md describing the per-model
  gen_statem admission, cache resolution, decode, and save
  pipeline.
• internals/c-safety-audit.md added to the HexDocs navigation.

Changed

• README rewritten for sharper top-of-funnel: tighter "Why" list,
  cleaner Quick taste, Common patterns block replacing the old
  long example.
• Architecture diagram corrected — erllama_cache_ramfile_srv
  and erllama_cache_disk_srv are operator-started standalone
  servers, not children of erllama_cache_sup. Added
  erllama_registry and erllama_inflight which were missing.
• "Inside a request" lifecycle updated for the multi-seq
  scheduler: two states (idle/running) instead of the v0.1
  three-phase model, with co-batched nif_step and inline
  thinking/tool-call marker recognition.