feat(ui): add legend card below the heatmap

The four-line description above the heatmap was concise but
opaque: 'X: log10 €/year. Y: 0–5. Punktgröße.' said the right
words, but a reviewer who isn't already methodologically
oriented can't tell what they're looking at.

Adds a dedicated Legende-Karte directly under the heatmap.
Four rows, each: leading symbol (↔ ↕ ● ◐), axis-or-quantity
label, prominent name (Schaden / Nutzen / Betroffenheit /
Evidenz-Stufe), and a short prose explanation tying the visual
back to the Studie:

  ↔  Abszisse (X)  Schaden       — log10 €/Jahr, SKM §3.1
  ↕  Ordinate (Y)  Nutzen        — 7-dim. Komposit §3.2
  ●  Punktgröße    Betroffenheit — sqrt scale, DESTATIS-/IHK
  ◐  Tier-Farbe    Evidenz-Stufe — Regel der niedrigsten §6.7

Top description tightened to one line of context only:
'Schaden × Nutzen × Betroffenheit pro Norm. Klick auf einen
Punkt öffnet das Detail …'. No redundancy with the legend,
no jargon up top.

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.

MACHBARKEITSSTUDIE.md

@@ -870,7 +870,7 @@ liegt dann woanders.
 4. **Rechtliche Kurz-Stellungnahme** anstoßen (EU AI Act,
    DSGVO, §5 UrhG, juris-Lizenz). Möglichst kostenneutral über
    Lehrstuhl-Kooperation.
-5. **Repo `fai/lawheatmap` initialisieren** (Forgejo unter `git.flemming.ai`,
+5. **Repo `fai/reclaim` initialisieren** (Forgejo unter `git.flemming.ai`,
    Vendor-Namespace `fai/`), Lizenz Apache 2.0, DCO an, CI-Pipeline analog
    `fai/chain` (DCO-Sign-off, Conventional Commits, SBOM, sigstore).
    `law.*`-Module später in `chain-modules-law/` als product-scoped Org.
@@ -890,7 +890,7 @@ liegt dann woanders.
 - **ELI**: European Legislation Identifier (eli.dlri.de / EUR-Lex)
 - **CELEX**: EU-Dokumenten-ID-System
 - **REFIT**: EU-Programm zur Regulatorischen Eignungsprüfung
-- **Ch∆In** (CLI: `chain`): Orchestrierungs-Plattform unter `fai_lawheatmap`. Vendor: **F∆I = Flemming.AI**.
+- **Ch∆In** (CLI: `chain`): Orchestrierungs-Plattform (eigenes Repo `fai_chain`), auf der Recl∆Im als Domänen-App aufsetzt. Vendor: **F∆I = Flemming.AI**.
 - **Hub / Module / Flow**: Ch∆In-Server (`chain serve`), WASM-Komponente (ABI `chain:platform`), YAML-Workflow
 - **RAG**: Retrieval Augmented Generation — LLM mit verpflichteter Quelleneinbindung
 - **Hochrisiko-KI (EU AI Act)**: KI-System, das Rechtsfolgen für Personen

METHODIK.md

@@ -297,5 +297,5 @@ Jede Methodik-Version benötigt:
 ---
 
 **Kontakt:** Dr. Stefan Flemming, F∆I (Flemming.AI),
-chain@flemming.ai. Repository: `git.flemming.ai/fai/lawheatmap`.
+chain@flemming.ai. Repository: `git.flemming.ai/fai/reclaim`.
 Lizenz: Apache-2.0.

app/lib/pages/heatmap_page.dart

@@ -50,9 +50,9 @@ class _HeatmapPageState extends State<HeatmapPage> {
                     Text('Heatmap', style: t.displaySmall),
                     const SizedBox(height: ReclaimSpace.xs),
                     Text(
-                      'X: jährliche Bürokratiekosten (€, log10). '
+                      'Schaden × Nutzen × Betroffenheit pro Norm. '
-                      'Y: Nutzen-Score 0–5. Punktgröße: Betroffenheit. '
+                      'Klick auf einen Punkt öffnet das Detail mit '
-                      'Klick auf einen Punkt → Detail mit Pflichten + Quellen.',
+                      'Pflichten, Quellen und Gesetzestext.',
                       style: t.bodyLarge?.copyWith(
                         color: ReclaimColors.mute,
                       ),
@@ -77,6 +77,8 @@ class _HeatmapPageState extends State<HeatmapPage> {
                         ),
                       ),
                     ),
+                    const SizedBox(height: ReclaimSpace.md),
+                    _LegendCard(),
                     const SizedBox(height: ReclaimSpace.lg),
                     Wrap(
                       spacing: ReclaimSpace.md,
@@ -126,3 +128,134 @@ class _HeatmapPageState extends State<HeatmapPage> {
     );
   }
 }
+
+/// Axis + circle legend below the heatmap. Spells out what is
+/// plotted and how — the four-line top description deliberately
+/// stays short and high-level, this card carries the precise
+/// reading instructions a reviewer needs to defend the plot
+/// against "what does that even mean?"
+class _LegendCard extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    final t = Theme.of(context).textTheme;
+    return ReclaimCard(
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text('Legende', style: t.headlineSmall),
+          const SizedBox(height: ReclaimSpace.md),
+          _LegendRow(
+            symbol: '↔',
+            axis: 'Abszisse (X)',
+            label: 'Schaden',
+            description:
+                'Bürokratiekosten pro Jahr in Euro, logarithmisch '
+                'skaliert (10⁴ = 10 k, 10⁶ = 1 Mio, 10⁹ = 1 Mrd). '
+                'Berechnet nach Standardkostenmodell '
+                'P × F × T × h (Studie §3.1).',
+          ),
+          const SizedBox(height: ReclaimSpace.sm),
+          _LegendRow(
+            symbol: '↕',
+            axis: 'Ordinate (Y)',
+            label: 'Nutzen',
+            description:
+                'Komposit-Score von 0–5, Mittelwert aus den sieben '
+                'Dimensionen Schutz · Markt · Rechtssicherheit · '
+                'EU-Binnenmarkt · Sicherheit · Umwelt · Einnahmen '
+                '(Studie §3.2). Jede Dimension einzeln '
+                'quellen-begründet.',
+          ),
+          const SizedBox(height: ReclaimSpace.sm),
+          _LegendRow(
+            symbol: '●',
+            axis: 'Punktgröße',
+            label: 'Betroffenheit',
+            description:
+                'Anzahl der Adressaten (KMU, Bürger, Behörden), '
+                'wurzel-skaliert. Mehr Adressaten → größerer Kreis. '
+                'Quellen: DESTATIS Unternehmensregister, '
+                'IHK-/Handwerkskammer-Mitgliederzahlen.',
+          ),
+          const SizedBox(height: ReclaimSpace.sm),
+          _LegendRow(
+            symbol: '◐',
+            axis: 'Tier-Farbe',
+            label: 'Evidenz-Stufe',
+            description:
+                'Petrol → warm-orange markiert die Stufe (T1–T4) der '
+                'schwächsten Eingangs-Variable. Eine SKM-Zahl mit '
+                'T4-Schätzwert für h trägt die ganze Zahl als T4 '
+                '(Regel der niedrigsten Stufe, Studie §6.7).',
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _LegendRow extends StatelessWidget {
+  const _LegendRow({
+    required this.symbol,
+    required this.axis,
+    required this.label,
+    required this.description,
+  });
+
+  final String symbol;
+  final String axis;
+  final String label;
+  final String description;
+
+  @override
+  Widget build(BuildContext context) {
+    final t = Theme.of(context).textTheme;
+    return Row(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        SizedBox(
+          width: 28,
+          child: Text(
+            symbol,
+            style: t.titleMedium?.copyWith(
+              color: ReclaimColors.signal,
+              fontSize: 18,
+            ),
+          ),
+        ),
+        SizedBox(
+          width: 140,
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Text(
+                axis,
+                style: t.labelSmall?.copyWith(
+                  color: ReclaimColors.mute,
+                  letterSpacing: 0.4,
+                ),
+              ),
+              Text(
+                label,
+                style: t.titleMedium,
+              ),
+            ],
+          ),
+        ),
+        const SizedBox(width: ReclaimSpace.md),
+        Expanded(
+          child: Padding(
+            padding: const EdgeInsets.only(top: 2),
+            child: Text(
+              description,
+              style: t.bodyLarge?.copyWith(
+                color: ReclaimColors.mute,
+                height: 1.5,
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}

app/web/index.html

@@ -18,18 +18,18 @@
 
   <meta charset="UTF-8">
   <meta content="IE=Edge" http-equiv="X-UA-Compatible">
-  <meta name="description" content="A new Flutter project.">
+  <meta name="description" content="Recl∆Im — Pflicht-basierte Wirkungsanalyse für Rechtsnormen, auf der Ch∆In-Plattform.">
 
   <!-- iOS meta tags & icons -->
   <meta name="mobile-web-app-capable" content="yes">
   <meta name="apple-mobile-web-app-status-bar-style" content="black">
-  <meta name="apple-mobile-web-app-title" content="reclaim_app">
+  <meta name="apple-mobile-web-app-title" content="Recl∆Im">
   <link rel="apple-touch-icon" href="icons/Icon-192.png">
 
   <!-- Favicon -->
   <link rel="icon" type="image/png" href="favicon.png"/>
 
-  <title>reclaim_app</title>
+  <title>Recl∆Im</title>
   <link rel="manifest" href="manifest.json">
 </head>
 <body>

app/web/manifest.json

@@ -1,11 +1,11 @@
 {
-    "name": "reclaim_app",
+    "name": "Recl∆Im",
-    "short_name": "reclaim_app",
+    "short_name": "Recl∆Im",
     "start_url": ".",
     "display": "standalone",
     "background_color": "#0175C2",
     "theme_color": "#0175C2",
-    "description": "A new Flutter project.",
+    "description": "Recl∆Im — Pflicht-basierte Wirkungsanalyse für Rechtsnormen, auf der Ch∆In-Plattform.",
     "orientation": "portrait-primary",
     "prefer_related_applications": false,
     "icons": [