agents: add AGENTS.md + .agents/ scaffolding (wiki/plans/skills stubs)

Adds the root AGENTS.md entry point and minimal .agents/ skeleton
(SOUL, wiki/master-plan+ARCHITECTURE, plans/, skills/) per the
per-repo-agents-convention. Existing handoffs/ untouched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

AGENTS.md

@@ -0,0 +1,32 @@
+# AGENTS.md — tinqs/builds
+
+## Identity
+
+Build artifact repo for the Tinqs/Ariki engine stack — engine editor binaries + matched
+`GodotSharp/` C# bindings, tracked in `manifest.json`. Not a codebase; source lives in
+`tinqs/engine`, `tinqs/ariki-game`, `tinqs/ariki-sim`.
+
+**Read the docs hub at session start:** `tinqs-ltd/docs/AGENTS.md` — shared identity, team roster,
+cross-repo rules. This file is the thin, repo-specific entry point; per-repo detail lives in
+`.agents/`.
+
+## Knowledge map (`.agents/`)
+
+| Path | Role | When |
+|---|---|---|
+| `.agents/SOUL.md` | Identity (inherits hub) | always-on |
+| `.agents/wiki/master-plan.md` | Current state + in-flight work | always-on |
+| `.agents/wiki/ARCHITECTURE.md` | Architecture law (entry point) | consult-when |
+| `.agents/wiki/architecture/` | Per-system architecture docs | consult-when |
+| `.agents/plans/` | Open/executing work (temporary — graduates to wiki) | consult-when |
+| `.agents/skills/` | Agent playbooks | consult-when |
+| `.agents/handoffs/` | Cross-machine task queue (e.g. `forge-windows-4.7.md`) | consult-when |
+
+Root `README.md` and `manifest.json` are the human-facing/data source of truth for what's actually
+shipped — read those for exact current contents.
+
+## Git
+
+- Branch: **main** only.
+- Sync with `tinqs push` / `tinqs pull` (LFS-heavy repo — never raw `git push`/`git pull`).
+- Commit with plain `git commit`.