feat(phase-14/42): add mission.md briefing

phases/14-agent-engineering/42-agent-workbench-capstone/mission.md

@@ -0,0 +1,27 @@
+# Mission - Capstone: Ship a Reusable Agent Workbench Pack
+
+## Goal
+Assemble the eleven prior lessons into a versioned `outputs/agent-workbench-pack/` directory with an installer that lays it idempotently into any target repo.
+
+## Inputs
+- Schemas, scripts, and docs from lessons 32 through 40
+- The pack layout: `AGENTS.md`, `docs/`, `schemas/`, `scripts/`, `bin/`, `README.md`, `VERSION`
+
+## Deliverables
+- `outputs/agent-workbench-pack/` with the full layout populated
+- `bin/install.sh` (or `bin/install.py`) that refuses to overwrite without `--force`
+- `VERSION` file plus a `README.md` describing what stays in and what stays out
+
+## Acceptance
+- `python3 code/main.py` exits zero and prints the pack tree
+- Re-running the assembler is idempotent
+- `bin/install.sh` into a fresh target leaves a working workbench: state, board, rules, scope, init, runner, gate, reviewer, handoff all in place
+
+## Out of scope
+- Per-project task content. Tasks belong on the target repo's board, not in the pack.
+- Vendor SDK calls. The pack is framework-agnostic by design.
+
+## References
+- `docs/en.md` - full lesson
+- `code/main.py` - reference implementation
+- `outputs/skill-workbench-pack.md` - extracted skill