Implement comprehensive CI/CD pipeline with best practices

Major improvements:
- Matrix testing across Linux (stable/beta/nightly), Windows, and macOS
- Test with multiple feature combinations (default, yara-scanning, no-default)
- Code coverage reporting with codecov integration
- Security auditing with cargo-audit and dependency review
- Automated release builds for multiple targets
- Performance benchmarking with trend tracking
- Concurrency control to cancel outdated runs
- Rust cache optimization for faster builds
- Documentation generation checks
- Weekly scheduled runs for proactive monitoring

Additional workflows:
- Automated dependency updates via Dependabot
- Weekly Cargo dependency update PRs
- Stale issue and PR management

Project templates:
- Pull request template with checklist
- Bug report issue template
- Feature request issue template
- Codecov configuration with 70% coverage target

.github/workflows/dependencies.yml

@@ -0,0 +1,36 @@
+name: Dependency Management
+
+on:
+  schedule:
+    - cron: '0 0 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update-dependencies:
+    name: Update Dependencies
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Update dependencies
+        run: cargo update
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v5
+        with:
+          commit-message: Update Cargo dependencies
+          title: 'chore: update Cargo dependencies'
+          body: |
+            Automated dependency update generated by GitHub Actions.
+
+            Please review the changes and ensure all tests pass before merging.
+          branch: deps/cargo-update
+          delete-branch: true