release(0.2.0): bump version from 0.1.5 to 0.2.0

This release carries the full post-audit work — 46 new indicators
(25 → 71), an eight-family taxonomy restructure, new bindings for
RollingVWAP, the WASM streaming-update parity, the pyo3/numpy CVE
fix, the SMA/Bollinger drift bound, the O(1) LinearRegression
refactor, the UlcerIndex deque and the PSAR is_ready/reset fixes
plus a refreshed example suite and wiki. The earlier 0.1.5 number
was never published; jumping straight to 0.2.0 is the cleaner signal
for the scope of the change.

Bumped:
- Cargo.toml workspace + wickra-core workspace-dep version
- bindings/python/pyproject.toml
- bindings/node/package.json + optionalDependencies (six platform pins)
- 6 x bindings/node/npm/<target>/package.json
- Cargo.lock regenerated
- CHANGELOG.md [0.2.0] header + compare-link
- docs/wiki/Home.md published-versions table
- docs/wiki/Quickstart-{Rust,Node,WASM}.md + Warmup-Periods.md
  version-pinned narrative lines

Verified locally:
- cargo fmt/clippy/test (628 passed, 0 failed)
- cargo deny check (no suppression)
- bindings/node node --test (92/92)
- bindings/python pytest (118/118)
- import wickra reports 0.2.0 with 72 indicator classes

docs/wiki/Home.md

@@ -26,12 +26,12 @@ open an issue on GitHub to discuss a separate license.
 
 | Registry  | Package        | Version |
 |-----------|----------------|---------|
-| crates.io | `wickra`       | 0.1.5   |
-| crates.io | `wickra-core`  | 0.1.5   |
-| crates.io | `wickra-data`  | 0.1.5   |
-| PyPI      | `wickra`       | 0.1.5   |
-| npm       | `wickra`       | 0.1.5   |
-| npm       | `wickra-wasm`  | 0.1.5   |
+| crates.io | `wickra`       | 0.2.0   |
+| crates.io | `wickra-core`  | 0.2.0   |
+| crates.io | `wickra-data`  | 0.2.0   |
+| PyPI      | `wickra`       | 0.2.0   |
+| npm       | `wickra`       | 0.2.0   |
+| npm       | `wickra-wasm`  | 0.2.0   |
 
 Release notes and tagged builds:
 <https://github.com/kingchenc/wickra/releases>.
@@ -47,7 +47,7 @@ Release notes and tagged builds:
 - [Quickstart: Node](Quickstart-Node.md) — `npm install wickra`, basic
   `SMA` and `MACD` calls, and the install surface. Windows x64 was
   previously blocked by an npm spam filter on `wickra-win32-x64-msvc`;
-  that was resolved with npm Support, and 0.1.5 is the first release in
+  that was resolved with npm Support, and 0.2.0 is the first release in
   which `npm install wickra` works end-to-end on Windows.
 - [Quickstart: WASM](Quickstart-WASM.md) — `npm install wickra-wasm`,
   building with `wasm-pack`, and running indicators client-side in a