docs: add reclaim agent CLAUDE.md (cross-agent boundaries)

Establish the per-session context for the reclaim agent: product
identity (Recl∆Im / reclaim_app), that this is a domain app on top
of the Ch∆In platform, the ownership boundary (platform + client
SDK belong to the chain agent — request changes via
shared/HANDOFFS.md, never edit them), and the confidentiality rule
that MACHBARKEITSSTUDIE.md is AG-intern. Points to
../../shared/AGENTS.md as the cross-agent charter.

Signed-off-by: flemming-it <sf@flemming.it>

CLAUDE.md

@@ -0,0 +1,58 @@
+# Recl∆Im — Context for Claude Code
+
+You are the **reclaim** agent. Read this first, every session.
+
+## Identity
+
+- **Product:** Recl∆Im (ASCII / code: `reclaim`) — a domain app for
+  law / duty reform-mapping (Pflicht-basierte Wirkungsanalyse).
+- **Flutter package:** `reclaim_app` (snake_case Dart identifier — this
+  stays; only user-facing display names use the `∆` spelling).
+- **Author:** Dr. Stefan Flemming, F∆I (Flemming.AI).
+- **Repository (dev):** `git.flemming.ai/fai/reclaim`.
+- **License:** Apache 2.0.
+
+> Naming: `∆` replaces the "AI" letters; in ASCII / code use the plain
+> spelling `reclaim`. The Dart package identifier `reclaim_app` and the
+> on-disk macOS bundle `reclaim_app.app` are code references and stay
+> snake_case; user-facing product strings read **Recl∆Im**.
+
+## What this is
+
+Recl∆Im is **a domain app built on top of the Ch∆In platform.** It
+consumes the platform — it is not the platform. It connects to a Ch∆In
+hub over gRPC via the `chain_client_sdk` (a path dependency) and runs
+WASM modules + YAML flows the hub orchestrates.
+
+## Cross-agent boundaries
+
+Read `../../shared/AGENTS.md` (the cross-agent charter) and
+`../../shared/HANDOFFS.md` (your task list) every session.
+
+- **You own:** the Recl∆Im Flutter app (`reclaim_app`) — its UI and
+  domain logic — plus Recl∆Im-specific flows / modules, branding, and
+  the Recl∆Im docs (METHODIK, RUN, MACHBARKEITSSTUDIE).
+- **You do NOT own** the platform. The hub, the `chain` CLI, the runtime
+  / sandbox, the module ABI (`chain:platform`), the gRPC wire
+  (`chain.v1`), Studio, and the client SDKs all belong to the **chain**
+  agent. Recl∆Im uses `chain_client_sdk` via a path dep but **never
+  modifies it.**
+- Need a new RPC / SDK method / ABI capability, or any change to the
+  hub / SDK / wire? Do **not** edit it — append a handoff row to
+  `../../shared/HANDOFFS.md` (from: reclaim, to: chain) and skip that
+  item.
+
+## Confidentiality
+
+The internal `MACHBARKEITSSTUDIE.md` is **AG-intern** and must never go
+into public docs, code, commits, or examples. Never name pilot
+institutions (ITDZ, Kammergericht, HTW, J∆I) or customer↔label mappings
+in public material. Generic terms only ("a regulated organization").
+
+## Commit conventions
+
+- Conventional commits in English: `type(scope): message`.
+- DCO sign-off on every commit: `git commit -s`
+  (`Signed-off-by: …`). No `Co-Authored-By` trailer.
+- Make the smallest change that works; verify with `flutter analyze`
+  (in `app/`) before claiming done where practical.