release(v4.9.0): Issue #50 / #55 - archive the review reports and bump the lockstep version

Merge review on macOS (--review-only loops, --all-reviewer): round 1 at
320aa9f 4/4 NOT PASS, round 2 codex F1 (a claimed dry-run job holds its
session), round 3 4/4 PASS (discarded: the worktree changed mid-review),
round 4 at 21f0c12 claude/agy/grok PASS with codex interrupted by a stream
disconnect, round 5 codex PASS. Full suite at 21f0c12 on macOS / Python
3.9 / bash 3.2 / herdr 0.9.3: 1860 passed / 0 failed / 38 skipped; no new
entries in ~/.claude/projects.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

.agents/skills/lib.sh

@@ -29,7 +29,7 @@ export WORKSPACE_ROOT
 # Framework semantic version. Single runtime source of truth; kept in lockstep
 # with VERSIONS.md and the 8 SKILL.md frontmatters by tests/test_version_consistency.py.
 # NOTE: unlike other MAM_* variables this one is intentionally NOT env-overridable.
-MAM_VERSION="4.8.9"
+MAM_VERSION="4.9.0"
 export MAM_VERSION
 AGENT_SESSIONS_YAML="${AGENT_SESSIONS_YAML:-$WORKSPACE_ROOT/.mam/agent-sessions.yaml}"