feat(release): self-determination - ensure at launch, drift warnings, M20 packages/* decision (#38)

- release.sh ensure: aligned no-op; drift -> package-if-needed + health-gated
  activate (M3 gate-then-flip, automated)
- ensure_release_aligned in common.sh: invoked by hello/verify/agent;
  MOSAIC_ENSURE_SKIP guards recursion; run-task warns on drift without
  auto-aligning (workers/suites never trigger builds or model gates)
- ROADMAP: M20 decision recorded - v2 adopts packages/* monorepo at usurpation
- BUILD-LOG Phase 20 + tool-race process note

Live-verified: post-reset pointer loss auto-restored via health-gated
ensure; drift warning fires on desired-version bump; idempotent no-op on
aligned state.

Closes #38

scripts/common.sh

@@ -55,3 +55,19 @@ bootstrap_runtime_dir() {
     # auto-invoked by agent.sh) creates it from the template.
     mkdir -p "$MOSAIC_DEV_DIR/user"
 }
+
+# M16 release self-determination: launchers call this after load_release.
+# Cheap no-op when the active pointer matches the desired RELEASE; on drift
+# it delegates to `release.sh ensure` (package if needed, health-gated
+# activate). The health gate's own task run sets MOSAIC_ENSURE_SKIP so the
+# ensure never re-enters itself.
+ensure_release_aligned() {
+    [ -n "${MOSAIC_ENSURE_SKIP:-}" ] && return 0
+    local pointer="$MOSAIC_DEV_DIR/state/active.json"
+    local active=""
+    if [ -f "$pointer" ]; then
+        active="$(node -e 'try{const p=JSON.parse(require("fs").readFileSync(process.argv[1],"utf8"));process.stdout.write(p.release||"")}catch{}' "$pointer" 2>/dev/null)"
+    fi
+    [ "$active" = "$MOSAIC_RELEASE" ] && return 0
+    MOSAIC_ENSURE_SKIP=1 scripts/release.sh ensure
+}