feat(aidd-context): rebuild onboard as a token-lean guided tutorial

aidd_docs/tasks/2026_07/2026_07_08_onboard-tutorial-rebuild/codex-portability.md

@@ -0,0 +1,49 @@
+# Codex portability — before and after the router fix
+
+The skill triggered on Codex from the start, but rendered nothing. Root cause: the
+'read an action's file before running it' rule had been moved into skill-authoring.md,
+a contract no executing host ever reads. Codex read SKILL.md and stopped.
+
+## Before — Codex reads SKILL.md and stops
+
+```text
+I'm using `aidd-context:00-onboard` because you asked to be onboarded.
+[reads .../skills/00-onboard/SKILL.md]
+[no banner, no setup block, no foundations screen — improvises a generic answer]
+```
+
+Full capture: `headless-runs-codex.txt` (all eight states, pre-fix).
+
+## After — the router carries the operative line
+
+`SKILL.md`: `Run the actions in that order, looping. Read an action's file in \`actions/\` before running it.`
+
+```text
+ █████╗ ██╗██████╗ ██████╗
+██╔══██╗██║██╔══██╗██╔══██╗
+███████║██║██║  ██║██║  ██║
+██╔══██║██║██║  ██║██║  ██║
+██║  ██║██║██████╔╝██████╔╝
+╚═╝  ╚═╝╚═╝╚═════╝ ╚═════╝
+ AI-Driven Development 🇫🇷
+
+exec
+/bin/zsh -lc "test -f AGENTS.md && sed -n '1,160p' AGENTS.md || true" in /private/tmp/aidd-demo/01-greenfield
+exec
+/bin/zsh -lc "test -f RTK.md && sed -n '1,220p' RTK.md || true" in /private/tmp/aidd-demo/01-greenfield
+ succeeded in 0ms:
+ succeeded in 0ms:
+exec
+/bin/zsh -lc "find . -maxdepth 2 -type f -o -type d | sort | sed -n '1,160p'" in /private/tmp/aidd-demo/01-greenfield
+ succeeded in 0ms:
+.
+./.git
+./.git/HEAD
+./.git/config
+./.git/description
+./.git/hooks
+./.git/info
+```
+
+Probes: READ THE ACTIONS ✓ · BANNER ✓ · SETUP BLOCK ✓ · FOUNDATIONS ✓
+Identical shape to the Claude run in `headless-runs.md`.