release: bump 0.9.4 -> 0.9.5 (#329)

Maintenance release. The library API and every indicator are unchanged from
`0.9.4`; the only change that ships to users is the R package's build script.

### What's in 0.9.5
- **R package: retry the C ABI download** (`bindings/r/configure[.win]`). A freshly
  cut release can briefly 404 while assets propagate; the download is now retried
  with a ~2 min backoff instead of failing with `cannot open URL … 404`. Landed in
  #328; ships to r-universe / source installs with this release.
- The rest of #328 — CI/release-pipeline hardening (R/NuGet dependency caching,
  job timeouts 20→30 / release 45, network-install retries, wasm-publish cache) —
  is infrastructure and does not affect the published artifacts, but makes this
  release's own pipeline more robust.

Pure version-string bump on top — `bump_version.py` touched 19 files (Cargo +
Lock, pyproject, node package.json/locks + 6 platform stubs, pom + csproj +
DESCRIPTION, SECURITY, CHANGELOG `[0.9.5]` + compare URLs). `cargo fmt` clean.

Tag/publish waits for explicit GO (irreversible publish to crates.io / PyPI /
npm / NuGet / Maven / Go / r-universe).

examples/java/pom.xml

@@ -6,7 +6,7 @@
 
   <groupId>org.wickra.examples</groupId>
   <artifactId>wickra-examples</artifactId>
-  <version>0.9.4</version>
+  <version>0.9.5</version>
   <packaging>jar</packaging>
 
   <name>Wickra Java examples</name>
@@ -21,7 +21,7 @@
     <dependency>
       <groupId>org.wickra</groupId>
       <artifactId>wickra</artifactId>
-      <version>0.9.4</version>
+      <version>0.9.5</version>
     </dependency>
   </dependencies>