release: bump 0.8.5 -> 0.8.6 (#260)

Version bump `0.8.5` → `0.8.6`.

### Changed
- Package registry metadata for better discoverability (#259):
  - R (R-universe): R-universe URL + `X-schema.org-keywords` in `DESCRIPTION`, package logo at `bindings/r/man/figures/logo.png`.
  - Python (PyPI): `Documentation` project URL.
  - C# (NuGet): package icon via `PackageIcon`.

Ships the metadata so the next PyPI/NuGet publish carries the new fields (R-universe rebuilds from main independently). Bump touches the manual release touchpoints only; docs/webpage version strings are left to `sync-about.yml` on the tag.

bindings/node/package.json

@@ -1,6 +1,6 @@
 {
   "name": "wickra",
-  "version": "0.8.5",
+  "version": "0.8.6",
   "description": "Streaming-first technical indicators: incremental, fast, install-free. Node bindings powered by Rust.",
   "author": "kingchenc <support@wickra.org>",
   "main": "index.js",
@@ -47,12 +47,12 @@
     "node": ">= 18"
   },
   "optionalDependencies": {
-    "wickra-linux-x64-gnu": "0.8.5",
-    "wickra-linux-arm64-gnu": "0.8.5",
-    "wickra-darwin-x64": "0.8.5",
-    "wickra-darwin-arm64": "0.8.5",
-    "wickra-win32-x64-msvc": "0.8.5",
-    "wickra-win32-arm64-msvc": "0.8.5"
+    "wickra-linux-x64-gnu": "0.8.6",
+    "wickra-linux-arm64-gnu": "0.8.6",
+    "wickra-darwin-x64": "0.8.6",
+    "wickra-darwin-arm64": "0.8.6",
+    "wickra-win32-x64-msvc": "0.8.6",
+    "wickra-win32-arm64-msvc": "0.8.6"
   },
   "scripts": {
     "build": "napi build --platform --release",