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>

bin/mosaic

@@ -56,6 +56,7 @@ PRD:
                          init    Create docs/PRD.md via guided runtime session
                          update  Update existing PRD via guided runtime session
                          validate Check PRD completeness (bash-only)
+                         status  Quick PRD health check (one-liner)
 
 Coordinator (r0):
   coord <subcommand>     Manual coordinator tools
@@ -183,6 +184,40 @@ MISSION_EOF
     fi
   fi
 
+  # Inject PRD status so the agent knows requirements state
+  local prd_file="docs/PRD.md"
+  if [[ -f "$prd_file" ]]; then
+    local prd_sections=0
+    local prd_assumptions=0
+    for entry in "Problem Statement|^#{2,3} .*(problem statement|objective)" \
+                 "Scope / Non-Goals|^#{2,3} .*(scope|non.goal|out of scope|in.scope)" \
+                 "User Stories / Requirements|^#{2,3} .*(user stor|stakeholder|user.*requirement)" \
+                 "Functional Requirements|^#{2,3} .*functional requirement" \
+                 "Non-Functional Requirements|^#{2,3} .*non.functional" \
+                 "Acceptance Criteria|^#{2,3} .*acceptance criteria" \
+                 "Technical Considerations|^#{2,3} .*(technical consideration|constraint|dependenc)" \
+                 "Risks / Open Questions|^#{2,3} .*(risk|open question)" \
+                 "Success Metrics / Testing|^#{2,3} .*(success metric|test|verification)" \
+                 "Milestones / Delivery|^#{2,3} .*(milestone|delivery|scope version)"; do
+      local pattern="${entry#*|}"
+      grep -qiE "$pattern" "$prd_file" 2>/dev/null && prd_sections=$((prd_sections + 1))
+    done
+    prd_assumptions=$(grep -c 'ASSUMPTION:' "$prd_file" 2>/dev/null || echo 0)
+
+    local prd_status="ready"
+    (( prd_sections < 10 )) && prd_status="incomplete ($prd_sections/10 sections)"
+
+    cat <<PRD_EOF
+
+# PRD Status
+
+- **File:** docs/PRD.md
+- **Status:** $prd_status
+- **Assumptions:** $prd_assumptions
+
+PRD_EOF
+  fi
+
   cat <<'EOF'
 # Mosaic Launcher Runtime Contract (Hard Gate)
 
@@ -639,6 +674,9 @@ run_prdy() {
     validate|check)
       MOSAIC_PRDY_RUNTIME="$runtime" exec bash "$tool_dir/prdy-validate.sh" "$@"
       ;;
+    status)
+      exec bash "$tool_dir/prdy-status.sh" "$@"
+      ;;
     help|*)
       cat <<PRDY_USAGE
 mosaic prdy — PRD creation and validation tools
@@ -647,6 +685,7 @@ Commands:
   init [--project <path>] [--name <feature>]   Create docs/PRD.md via guided runtime session
   update [--project <path>]                    Update existing docs/PRD.md via guided runtime session
   validate [--project <path>]                  Check PRD completeness against Mosaic guide (bash-only)
+  status [--project <path>] [--format short|json]  Quick PRD health check (one-liner)
 
 Runtime:
   --claude                    Use Claude runtime (default)