chore(release): 1.2.0 (#30)

Bump 1.1.4 -> 1.2.0 across all release files (Cargo, pyproject, wasm,
conda, docs) and roll the CHANGELOG [Unreleased] section into [1.2.0].

Highlights: runtime CPU-feature dispatch (multiversion), broader wheel
coverage (linux aarch64 + musllinux + windows arm64), abi3 wheels,
Dynamic Time Warping, and indicator-specific exception types.

wasm/package.json

@@ -1,6 +1,6 @@
 {
   "name": "ferro-ta-wasm",
-  "version": "1.1.4",
+  "version": "1.2.0",
   "description": "WebAssembly bindings for ferro-ta technical analysis indicators",
   "main": "node/ferro_ta_wasm.js",
   "module": "web/ferro_ta_wasm.js",