feat: add prdy-status command and PRD status injection into system prompt

- Add prdy-status.sh for quick one-liner PRD health check (short/json output)
- Inject PRD section count and assumption count into agent system prompt
  so the agent knows PRD state at session start without running validate
- Add status subcommand to mosaic prdy routing and help text

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

tools/prdy/prdy-status.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+set -euo pipefail
+#
+# prdy-status.sh — Quick PRD health check (one-liner output)
+#
+# Usage:
+#   prdy-status.sh [--project <path>] [--format short|json]
+#
+# Exit codes:
+#   0 = PRD ready (all required sections present)
+#   1 = PRD incomplete
+#   2 = PRD missing
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/_lib.sh"
+
+# ─── Parse arguments ─────────────────────────────────────────────────────────
+
+PROJECT="."
+FORMAT="short"
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --project) PROJECT="$2"; shift 2 ;;
+    --format)  FORMAT="$2"; shift 2 ;;
+    -h|--help)
+      cat <<'USAGE'
+prdy-status.sh — Quick PRD health check
+
+Usage: prdy-status.sh [--project <path>] [--format short|json]
+
+Options:
+  --project <path>  Project directory (default: CWD)
+  --format <f>      Output format: short (default) or json
+
+Exit codes:
+  0 = PRD ready (all required sections present)
+  1 = PRD incomplete
+  2 = PRD missing
+USAGE
+      exit 0
+      ;;
+    *) echo "Unknown option: $1" >&2; exit 1 ;;
+  esac
+done
+
+PROJECT="${PROJECT/#\~/$HOME}"
+
+# ─── Status check ────────────────────────────────────────────────────────────
+
+PRD_PATH="$(find_prd "$PROJECT")"
+
+if [[ -z "$PRD_PATH" ]]; then
+  if [[ "$FORMAT" == "json" ]]; then
+    echo '{"status":"missing"}'
+  else
+    echo "PRD: missing"
+  fi
+  exit 2
+fi
+
+# Count present sections using the shared manifest
+PRD_CONTENT="$(cat "$PRD_PATH")"
+total=${#PRDY_REQUIRED_SECTIONS[@]}
+present=0
+
+for entry in "${PRDY_REQUIRED_SECTIONS[@]}"; do
+  pattern="${entry#*|}"
+  if echo "$PRD_CONTENT" | grep -qiE "$pattern"; then
+    present=$((present + 1))
+  fi
+done
+
+# Count additional metrics
+fr_count=$(echo "$PRD_CONTENT" | grep -cE '^\- FR-[0-9]+:|^FR-[0-9]+:' || true)
+us_count=$(echo "$PRD_CONTENT" | grep -cE '^#{1,4} US-[0-9]+' || true)
+assumptions=$(echo "$PRD_CONTENT" | grep -c 'ASSUMPTION:' || true)
+
+if (( present == total )); then
+  status="ready"
+  exit_code=0
+else
+  status="incomplete"
+  exit_code=1
+fi
+
+if [[ "$FORMAT" == "json" ]]; then
+  printf '{"status":"%s","sections":%d,"total":%d,"frs":%d,"stories":%d,"assumptions":%d}\n' \
+    "$status" "$present" "$total" "$fr_count" "$us_count" "$assumptions"
+else
+  echo "PRD: $status ($present/$total sections, ${fr_count} FRs, ${us_count} stories, $assumptions assumptions)"
+fi
+
+exit "$exit_code"