feat: initial commit

AGENTS.md

@@ -0,0 +1,39 @@
+# Project AGENTS Router
+
+Root `AGENTS.md` is routing + cross-domain policy only.
+Do not place backend/frontend implementation details here.
+
+## Scope
+
+- Applies to repository root and cross-domain tasks.
+- Subdomain rules: `backend/AGENTS.md`, `apps/AGENTS.md`.
+- If rules conflict, use the stricter one.
+
+## Rule Order
+
+1. System / developer / platform safety instructions
+2. Workspace runtime rules (`AGENTS.md` + `rules/*`)
+3. This file (routing + project-level constraints)
+4. Subdomain rules (backend/apps)
+
+## Mandatory Routing
+
+- `backend/**` must follow `backend/AGENTS.md`.
+- `apps/**` must follow `apps/AGENTS.md`.
+- Cross-domain changes must satisfy all relevant subdomain rules.
+- `infra/**` follows this file plus `infra/` conventions.
+
+## Project-Wide Constraints
+
+- Default development branch is `dev`; do not develop directly on `main`.
+- Never push unless explicitly requested by the user.
+- Keep AGENTS layered and lean: shared rules at root, domain rules in sub-AGENTS.
+- **No Error Swallowing**: All exceptions must propagate or be converted to typed errors. Never catch an exception, log it, and silently continue. This destroys debuggability.
+
+## Protocol Source of Truth
+
+`docs/protocols/` is the single source of truth for protocol and data format.
+
+- Update protocol docs before changing data/API/UI contracts.
+- Document compatibility strategy (backward-compatible vs migration).
+- Keep frontend/backend implementations aligned with documented protocol.