* feat(c-abi): expose warmup_period / is_ready across the C ABI bindings
The C ABI hub exposed new/update/batch/reset/free per indicator but not the
Indicator::warmup_period / is_ready queries that the native (Python/Node/WASM)
bindings already had, so C/C#/Go/Java/R callers could not ask an indicator
whether it was warmed up without feeding it and watching for NaN.
Regenerated from the ScriptHelpers capi + language generators:
- bindings/c: wickra_<ind>_warmup_period (size_t) and wickra_<ind>_is_ready
(bool) for every indicator (504; the 10 alt-chart bar builders are excluded
by design). wickra.h regenerated via cbindgen (additive only).
- bindings/csharp: int WarmupPeriod() / bool IsReady() on each wrapper.
- bindings/go: WarmupPeriod() int / IsReady() bool.
- bindings/java: int warmupPeriod() / boolean isReady().
- bindings/r: C glue + registration; hand-written warmup_period() / is_ready()
S3 generics in methods.R, plus NAMESPACE exports.
Tests: C-ABI Rust unit tests, the C examples/archetypes.c suite, and the C#,
Go, Java and R archetype suites all gain a warmup/is_ready transition check.
* build(go): sync vendored wickra.h with the C ABI header
The Go binding vendors bindings/c/include/wickra.h; refresh it with the new
warmup_period / is_ready declarations so the CI sync check passes.
## What
Introduces `wickra-c` — a `cdylib` + `staticlib` that exposes the Rust core over a **C ABI**. This is the hub every C-capable language (C, C++, Go, C#, Java, R) links against, instead of re-wiring each indicator natively. The native Python/Node/WASM bindings are untouched; this is purely additive, for ecosystems without first-class Rust tooling.
## Scope (foundation slice)
This PR deliberately validates the **whole pipeline end to end with one indicator (SMA)** before scaling to all 514, so the CI / cross-OS / header-drift mechanics are proven green first.
- Opaque `*mut T` handles; `wickra_<ind>_{new,update,batch,reset,free}`.
- NaN sentinel for warmup / NULL handles; caller-owned batch buffers; every function NULL-safe.
- cbindgen generates and commits `bindings/c/include/wickra.h` with opaque handle typedefs.
- A C smoke example (`examples/c/`) links the header + compiled library and runs (CMake + ctest).
- A `c-abi` CI job builds the library and runs the smoke test on **Linux, macOS and Windows**, plus a header drift check on Linux.
## Notes
- The per-indicator FFI blocks are plain `#[no_mangle]` functions, **not** a macro: cbindgen cannot see macro-generated functions on stable Rust (macro expansion needs nightly), so the blocks are written literally and will be generated mechanically by the ScriptHelpers `capi` wrapper in a follow-up (same model as the committed-but-generated Node `index.js`).
- `bindings/c` cannot inherit the workspace `forbid(unsafe_code)` lint (the C boundary needs raw pointers), so it mirrors every workspace lint and only relaxes `unsafe_code`. The Rust core stays `unsafe`-forbidden.
## Follow-ups (separate PRs)
- ScriptHelpers `capi` generator + wire the scalar family (~235).
- Hand-written blocks for multi-output / custom-input / bars (~279).
- Docs consistency wave (README / docs / webpage: Python·Node·WASM·Rust → +C).
- Release wiring (native-lib matrix + header/lib GH-release assets) — gated.
kingchenc