release: bump 0.5.9 -> 0.6.0 (#190)

Version bump for the **v0.6.0** release (ships the B5 Volatility & Bands batch, #189 — 423 -> 429 indicators).

Bumps version strings across Cargo workspace, pyproject, node package.json + 6 platform packages, both package-lock.json files, and Cargo.lock; CHANGELOG `[Unreleased]` -> `[0.6.0]`. No code changes.

Versioning note: patch never reaches two digits — `0.5.9` rolls to the next minor `0.6.0` (not 0.5.10).

bindings/node/npm/darwin-x64/package.json

@@ -1,6 +1,6 @@
 {
   "name": "wickra-darwin-x64",
-  "version": "0.5.9",
+  "version": "0.6.0",
   "description": "Native binding for wickra (macOS Intel). Installed automatically as an optional dependency of wickra on matching platforms.",
   "main": "wickra.darwin-x64.node",
   "files": [