release(v4.8.3): bump framework and eight skills to 4.8.3 in lockstep; archive PR #46 reviews (two rounds)

Issue #42 stages 1-2: the SKILL.md code-block inventory as test data and
the removal of blocks the entry scripts already do. Merge-workspace review:
round 1 (@8d26106) claude agy grok PASS, codex NOT PASS (R1-R3); fixed in
17eba09 (docs, inventory data and the guard test only); round 2 4/4 PASS.
Full suite at 8d26106 1408 passed / 0 failed. Reports and the round-2
identity sidecars go to .agents/reports/<session>/.

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="4.8.2"
+MAM_VERSION="4.8.3"
 export MAM_VERSION
 AGENT_SESSIONS_YAML="${AGENT_SESSIONS_YAML:-$WORKSPACE_ROOT/.mam/agent-sessions.yaml}"