Loki Mode v7.21.0

Added

• AGENTS.md support. Loki now points the agent at AGENTS.md in the repository
  root for build, test, and style conventions, falling back to CLAUDE.md when
  AGENTS.md is absent (nearest-file-wins, never merged). AGENTS.md is the
  emerging cross-tool agent-config standard (read by Claude Code, Codex, Cursor,
  Aider, and others), so repos that adopt it now drive Loki without a
  Loki-specific config. The instruction line is byte-identical across the bash
  and Bun routes; the layered project-graph walker (autonomy/lib/project-graph.sh)
  prefers AGENTS.md over CLAUDE.md at each directory layer. Three new tests cover
  the walker precedence, prompt emission, and cross-route byte-parity.

Fixed

• Dual-route parity: the Bun route's no-PRD CODEBASE_ANALYSIS_MODE instruction
  was still the pre-v7.8.1 short prompt while the bash route had the v7.8.1
  three-pass version. The byte-exact fixture corpus masked this because both the
  Bun constant and the gold fixtures held the same stale string. The Bun
  ANALYSIS_INSTRUCTION is now byte-identical to the bash route, and the no-PRD
  fixtures were regenerated from the canonical bash output. No fixtures are
  suppressed (KNOWN_FAILING_FIXTURES stays empty); parity is genuinely green.