v0.3.1

Codex integration and cross-platform release hardening. No detection-rule
changes; the 35-rule detection set is unchanged.

Added

• MCP-level agent workflow instructions. Clients now receive the recommended
  scan → explain → consent → fix → rescan workflow during initialization, including
  granular fix consent, git-safety guidance, secret-rotation reminders, and the rule
  that a finding is never called fixed until a rescan confirms it.
• Native portability CI. Windows x64, macOS Intel, and Linux ARM64 now build,
  run unit tests and the MCP transport smoke, install and verify the pinned engines,
  require all 17 evals to execute, run the redaction e2e, and scan the fixture app.

Fixed

• Windows SARIF paths. Absolute paths emitted by Opengrep are now normalized
  against Windows backslash targets, so findings retain repository-relative file
  locations across every supported runtime.
• Accurate Codex setup documentation. Codex now uses its CLI command, settings
  UI, or config.toml instead of the Claude JSON example. The documented
  tool_timeout_sec = 600 prevents Codex's 60-second default from ending legitimate
  large-repository scans early. Existing Claude setup remains unchanged.
• GitHub Actions Node.js deprecation warnings. Checkout, Node setup, and artifact
  actions now use immutable Node 24-based release SHAs. The retired macos-13
  Intel runner label is replaced with macos-15-intel.

Internal

• The MCP stdio smoke now requires non-empty server instructions and checks that the
  critical consent/rescan guidance is present in the initialization handshake.