Add the Go binding over the C ABI hub (#228)

Adds a Go binding (`bindings/go`) over the C ABI hub — the second language stecker after C#.

## What's here
- **`bindings/go`** — a cgo binding exposing all 514 indicators as idiomatic Go types with `New<Indicator>` constructors and `Update`/`Batch`/`Reset`/`Close` methods. The wrappers in `indicators_gen.go` are generated from `bindings/c/include/wickra.h` (same archetype taxonomy as the C# generator: scalar/batch, multi-output, bars, profile, profile-values, array-input). Opaque handles are freed by `Close()` with a `runtime.SetFinalizer` backstop; pointer arguments are caller-owned, panics never cross the boundary.
- **`examples/go`** — the full example suite mirroring C/C#: streaming, backtest, multi_timeframe, parallel_assets (goroutine fan-out), three strategies, and `fetch_btcusdt`/`live_binance`.
- **CI** — a `go` job builds the C ABI library, stages it, and runs `gofmt`/`go vet`/`go test` plus the offline examples on Linux, macOS and Windows.
- **Docs** — Go added to the README languages table, project layout, building/testing, CONTRIBUTING binding table + regenerate note, ARCHITECTURE, examples index, issue/PR templates, the About-description template, and the other binding READMEs.

## Linking / distribution
The binding links the prebuilt C ABI library via cgo (`libwickra.so`/`.dylib`/`wickra.dll` staged under `bindings/go/lib`, gitignored). The native libraries are already shipped per target triple by the existing `c-abi-build` release job; distribution is via the subdirectory module tag `bindings/go/vX.Y.Z` (gated), so `release.yml` needs no new publish job.

No Rust crate or `Cargo.toml` change — the Go module is standalone and additive.

Not for merge yet (gated, per request).

CONTRIBUTING.md

@@ -23,6 +23,7 @@ licensed as above, without any additional terms or conditions.
 | `bindings/wasm` | wasm-bindgen bindings (`wickra-wasm` on npm). |
 | `bindings/c` | C ABI — `cdylib` + `staticlib` + generated `include/wickra.h`. The hub for C / C++ and any C-capable language. |
 | `bindings/csharp` | .NET binding over the C ABI (`Wickra` on NuGet) — `[LibraryImport]` P/Invoke generated from `wickra.h`. |
+| `bindings/go` | Go binding over the C ABI via cgo (module tag `bindings/go/vX.Y.Z`) — wrappers generated from `wickra.h`. |
 | `examples/` | Runnable examples. |
 | `docs/` | Pointer to the documentation site (docs.wickra.org); the docs live in the `wickra-lib/wickra-docs` repo. |
 
@@ -108,6 +109,8 @@ installed. Dependabot also keeps the `.github/requirements` pins current.
   (`bindings/c`) is generated from the core, so regenerate it from the core and
   commit `src/lib.rs` + `include/wickra.h`. The C# binding (`bindings/csharp`) is
   generated from `wickra.h`, so regenerate and commit its `Generated/*.g.cs` too.
+  The Go binding (`bindings/go`) is likewise generated from `wickra.h`, so
+  regenerate and commit `indicators_gen.go` (`gofmt`-clean).
 - **Docs.** Update the relevant page on the
   [documentation site](https://docs.wickra.org) and the
   `README.md` when behaviour or the public API changes. The docs live in