feat: export current graph as grammar with copy button for external AI analysis

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/CausalLab.tsx

@@ -538,6 +538,65 @@ function applyGrammarOps(state: EditorState, ops: GrammarOp[]): { state: EditorS
   return { state: s, errors }
 }
 
+function graphToGrammar(state: EditorState): string {
+  const lines: string[] = []
+
+  if (state.nodes.length) {
+    lines.push(`# Nœuds (${state.nodes.length})`)
+    for (const n of state.nodes) {
+      let l = `+node id=${n.id} label="${n.label}" type=${n.type} x=${n.x} y=${n.y}`
+      if (n.instrument) l += ` instrument=${n.instrument}`
+      if (n.unit)       l += ` unit=${n.unit}`
+      if (n.formula)    l += ` formula="${n.formula}"`
+      lines.push(l)
+    }
+    lines.push('')
+  }
+
+  if (state.edges.length) {
+    lines.push(`# Arêtes (${state.edges.length})`)
+    for (const e of state.edges) {
+      const sg = e.sign === 'positive' ? '+' : e.sign === 'negative' ? '-' : '='
+      let l = `+edge from=${e.from} to=${e.to} sign=${sg}`
+      if (e.strength != null && e.strength !== 2) l += ` s=${e.strength}`
+      if (e.style === 'dashed') l += ` style=dashed`
+      if (e.label)              l += ` label="${e.label}"`
+      if (e.lag_days != null)   l += ` lag=${e.lag_days}`
+      if (e.decay_days === null) l += ` decay=null`
+      else if (e.decay_days != null) l += ` decay=${e.decay_days}`
+      lines.push(l)
+    }
+    lines.push('')
+  }
+
+  const coefs = Object.entries(state.coefficients)
+  if (coefs.length) {
+    lines.push(`# Coefficients (${coefs.length})`)
+    for (const [key, c] of coefs) {
+      let l = `+coef key=${key} value=${c.value}`
+      if (c.description) l += ` desc="${c.description}"`
+      lines.push(l)
+    }
+    lines.push('')
+  }
+
+  const inputs = Object.entries(state.inputMapping)
+  if (inputs.length) {
+    lines.push(`# Inputs (${inputs.length})`)
+    for (const [node, m] of inputs) {
+      let l = `~input node=${node} source=${m.source}`
+      if (m.key) l += ` key=${m.key}`
+      lines.push(l)
+    }
+    lines.push('')
+  }
+
+  if (state.instruments.length)
+    lines.push(`~instruments ${state.instruments.join(',')}`)
+
+  return lines.join('\n').trim()
+}
+
 const GRAMMAR_REFERENCE = `# Nœuds
 +node id=<id> label="<texte>" type=<macro_event|observable|latent|market_asset> [x=<n>] [y=<n>] [instrument=<str>]
 ~node id=<id>  [label="..."] [type=...] [x=<n>] [y=<n>] [instrument=<str>]
@@ -1103,7 +1162,9 @@ function TabEditor({ initialId }: { initialId?: number | null }) {
   const [grammarApplied, setGrammarApplied] = useState(0)  // count of applied ops
   const [aiLoading, setAiLoading]       = useState(false)
   const [aiError, setAiError]           = useState<string | null>(null)
-  const [showGrammarRef, setShowGrammarRef] = useState(false)
+  const [showGrammarRef, setShowGrammarRef]     = useState(false)
+  const [showGrammarExport, setShowGrammarExport] = useState(false)
+  const [copied, setCopied]                     = useState(false)
   const svgRef                      = useRef<SVGSVGElement>(null)
 
   useEffect(() => {
@@ -1837,6 +1898,41 @@ function TabEditor({ initialId }: { initialId?: number | null }) {
             </pre>
           )}
 
+          {/* Export — grammaire courante du graphe */}
+          <div className="rounded border border-slate-700/50 overflow-hidden">
+            <button
+              onClick={() => setShowGrammarExport(v => !v)}
+              className="w-full flex items-center justify-between px-3 py-2 bg-dark-800/60 hover:bg-dark-800 text-xs text-slate-400 transition-colors">
+              <span className="flex items-center gap-1.5">
+                <Copy className="w-3 h-3" />
+                Grammaire courante du graphe
+                <span className="text-slate-600">
+                  ({state.nodes.length} nœuds · {state.edges.length} arêtes)
+                </span>
+              </span>
+              <span className="text-slate-600">{showGrammarExport ? '▲' : '▼'}</span>
+            </button>
+            {showGrammarExport && (() => {
+              const grammar = graphToGrammar(state)
+              return (
+                <div className="relative">
+                  <pre className="text-[10px] font-mono text-slate-400 bg-dark-900/80 p-3 overflow-x-auto max-h-52 leading-relaxed whitespace-pre">
+                    {grammar}
+                  </pre>
+                  <button
+                    onClick={() => {
+                      navigator.clipboard.writeText(grammar)
+                      setCopied(true)
+                      setTimeout(() => setCopied(false), 2000)
+                    }}
+                    className="absolute top-2 right-2 flex items-center gap-1 px-2 py-1 bg-slate-700 hover:bg-slate-600 rounded text-[10px] text-slate-300 border border-slate-600 transition-all">
+                    {copied ? '✓ Copié' : <><Copy className="w-2.5 h-2.5" /> Copier</>}
+                  </button>
+                </div>
+              )
+            })()}
+          </div>
+
           <textarea
             value={grammarText}
             onChange={e => { setGrammarText(e.target.value); setGrammarErrors([]); setGrammarApplied(0) }}