Add workflow-architect agent; raise team to 13 agents

- New workflow-architect subagent: FSM-first modeling with explicit
  model-selection strategy (statechart, DAG, decision tree, BPMN, Petri,
  saga, etc.), gap detection, failure/recovery as first-class, output
  spec format, and role fence vs Architect/Orchestrator.
- Orchestrator: add Workflow Architect to Specialist Map, roster,
  dispatch rule, workflow-modeling classification, handoff decision,
  final rules, and explicit dynamic agent selection (not a fixed
  pipeline).
- Installer EXPECTED_COUNT 12->13; docs/README/PROMPT_INSTALL updated;
  AgentsReport/workflow-architect seeded.

scripts/install.sh

@@ -1,14 +1,14 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-# Install the 12 dev_agent_team opencode agents into a local opencode config.
+# Install the 13 dev_agent_team opencode agents into a local opencode config.
 #
 # Usage:   ./scripts/install.sh
 # Override target dir with: OPENCODE_AGENTS_DIR=/some/dir ./scripts/install.sh
 
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 TARGET="${OPENCODE_AGENTS_DIR:-$HOME/.config/opencode/agents}"
-EXPECTED_COUNT=12
+EXPECTED_COUNT=13
 KEEP_BACKUPS=5
 
 echo "==> dev_agent_team installer"