docs: add agent bootstrap and contract read router

rules/ai/codex/AGENTS.template.md

@@ -0,0 +1,24 @@
+# {{ .project_name }} — Instructions for Codex
+
+## Shared Engineering Rules
+Read `bible/AGENT-BOOTSTRAP.md` first.
+Do not read the whole `bible/` submodule by default.
+Read only the contracts that `AGENT-BOOTSTRAP.md` routes you to for the current task.
+
+## Project Architecture
+Read `bible-local/README.md` first, then only the relevant project-specific architecture files.
+Every architectural decision specific to this project must be recorded in `bible-local/`.
+
+---
+
+## Minimum Read Path
+
+1. `bible/AGENT-BOOTSTRAP.md`
+2. `bible-local/README.md`
+3. Relevant files in `bible-local/architecture/` and `bible-local/decisions/`
+4. Relevant `bible/rules/patterns/*/contract.md`
+
+## Default Rule
+
+Do not claim you "read bible" unless you actually read the relevant files.
+Do not walk all shared contracts unless the task is explicitly about changing the rules library itself.