docs(readme): tool calling is verified per family, not "experimental / not reliable yet"

[michalharakal]

Why

The README still carried the May 2026 status wording that tool calling "is not reliable yet" and "may fail to trigger or parse even when plain generation works". Since 0.53.0 the NATIVE providers are verified end-to-end on real checkpoints by model-gated smoke tests (CHANGELOG: Verified — tool calling against engine 0.53.0, plus the Qwen3 chat-template rewrite in the same release). The wording undersells what the changelog already documents.

What

• Feature bullet: drop "(experimental)" and "not reliable yet"; list the families with NATIVE providers, name the smoke tests that verify them on real checkpoints, keep the GENERIC fallback described as best-effort, and note that zero-shot tool-call quality is still the model's (Qwen2.5-0.5B figures from 0.57.0).
• Status warning: keep the disclaimer, but scope the "can fail to trigger or parse" example to the GENERIC fallback and link the native-vs-generic table.
• Near-term roadmap: drop "including tool calling"; state the one real gap, there is no Llama 3 real-checkpoint smoke test yet.

Proof

Re-run 2026-10-09 against engine 0.57.0 (develop @ 2f80182, Linux x86_64, i7-9750H, JDK 25). JUnit XML checked: no test case skipped.

Test	Model	Result
:llm-runtime:kllama QwenToolCallSmokeTest	Qwen3-0.6B Q8_0	2 passed, 0 skipped, 61.9 s
:llm-runtime:kgemma FunctionGemmaOfficialGgufTest	FunctionGemma 270M Q8_0	3 passed, 0 skipped, 12.1 s

Qwen3 output through the auto-detected qwen provider (family=qwen, arch=qwen3):

<tool_call>
{"name": "calculator", "arguments": {"expression": "17 * 23"}}
</tool_call>

parsed, calculator executed by the agent loop, final answer produced.

FunctionGemma output (OFFICIAL style):

<start_function_call>call:get_weather{location:<escape>Paris<escape>}<end_function_call>

parsed get_weather call; template tokens and prompt tokenization pinned against the llama.cpp reference.

Not re-run here because the checkpoints are not cached on this machine: Gemma4E2BToolCallSmokeTest, SmolLM2ToolCallSmokeTest; both are recorded green in the 0.53.0 changelog entry.

Scope

README only, no code change.