Add masking shape classifier and guard tests for adversarial resistance

- Implemented tests for masking shape classifier resistance against threshold attacks, ensuring that blurring reduces accuracy and increases overlap between classes.
- Added tests for masking shape guard functionality, verifying that it maintains expected behavior under various conditions, including timeout paths and clean EOF scenarios.
- Introduced helper functions for calculating accuracy and handling timing samples to support the new tests.
- Ensured that the masking shape hardening configuration is properly utilized in tests to validate its effectiveness.

.github/workflows/build-openbsd.yml

@@ -1,34 +0,0 @@
-name: Build telemt for OpenBSD aarch64
-
-on:
-  workflow_dispatch:
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Compile in OpenBSD VM
-        uses: vmactions/openbsd-vm@v1
-        with:
-          release: "7.8"
-          arch: aarch64
-          usesh: true
-          sync: sshfs
-          envs: 'RUSTFLAGS'
-          prepare: |
-            pkg_add rust
-          run: |
-            cargo build --release
-        env:
-          RUSTFLAGS: "-C target-cpu=cortex-a53 -C target-feature=+aes,+pmull,+sha2,+sha1,+crc -C opt-level=3"
-
-      - name: Upload artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: telemt-openbsd-aarch64
-          path: target/release/telemt
-          retention-days: 7