chore(release): bump framework and 8 skills to v4.0.0 (MAJOR — cline removal & hermes modernization)

- Bump MAM_VERSION to 4.0.0 in lib.sh
- Bump all 8 skill frontmatter versions to 4.0.0 in 3-way lockstep
- Update VERSIONS.md with v4.0.0 changelog, migration guide (B-1..B-5), and skill matrix
- Archive multi-agent version upgrade consensus and peer review reports (439 passed, 0 failures)

.agents/skills/multi-agent-mux-status/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: multi-agent-mux-status
 description: "Read-only instant snapshot of all agent herdr sessions — name, YAML status, herdr alive, pane cmd/cwd, resume UUID on disk, and any drift. No mutation. Reuses reconcile.sh --dry-run for the diff logic. Use when you want to know 'what's running RIGHT NOW' without spinning up the monitor loop."
-version: 3.1.0
+version: 4.0.0
 author: godopu
 license: MIT
 platforms: [linux, macos]