chore: planning gate — milestones, issues, and task breakdown

Break PRD into 8 milestones (Phase 0–7) with 59 issues on Gitea.
Populate TASKS.md, update mission manifest, initialize scratchpad.
Repo created at git.mosaicstack.dev/mosaic/mosaic-stack.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/agent/critical.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+source "$SCRIPT_DIR/common.sh"
+
+ensure_repo_root
+load_repo_hooks
+
+if declare -F mosaic_hook_critical >/dev/null 2>&1; then
+  run_step "Run repo critical hook" mosaic_hook_critical
+else
+  echo "[agent-framework] No repo critical hook configured (.mosaic/repo-hooks.sh)"
+  echo "[agent-framework] Define mosaic_hook_critical() for project-specific priority scans"
+fi