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

Cargo.lock

@@ -1941,7 +1941,7 @@ dependencies = [
 
 [[package]]
 name = "wickra"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "approx",
  "criterion",
@@ -1952,7 +1952,7 @@ dependencies = [
 
 [[package]]
 name = "wickra-core"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "approx",
  "proptest",
@@ -1962,7 +1962,7 @@ dependencies = [
 
 [[package]]
 name = "wickra-data"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "approx",
  "csv",
@@ -1989,7 +1989,7 @@ dependencies = [
 
 [[package]]
 name = "wickra-node"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "napi",
  "napi-build",
@@ -1999,7 +1999,7 @@ dependencies = [
 
 [[package]]
 name = "wickra-python"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "numpy",
  "pyo3",
@@ -2008,7 +2008,7 @@ dependencies = [
 
 [[package]]
 name = "wickra-wasm"
-version = "0.1.5"
+version = "0.2.0"
 dependencies = [
  "console_error_panic_hook",
  "js-sys",