feat: add GET /api/search?q=...&format=md for AI/LLM consumption

New endpoint returns all matching documents as concatenated plain-text
markdown, one section per document separated by ---.

Format:
  # Document: {title}
  ID: {id} | Category: {category} | Date: {date} | Vendor: {vendor}

  {full_text or summary}

  ---

Parameters:
  q      - search query (required)
  format - must be 'md' (required; distinguishes from HTML search)

Uses same FTS5 search as existing endpoints, limit raised to 200.
Falls back to LIKE search if FTS5 fails. Returns text/markdown content type.
POST /api/search (HTML partial) unchanged.

main.go

@@ -98,6 +98,7 @@ func main() {
 	r.Get("/search", searchHandler)
 
 	// API endpoints
+	r.Get("/api/search", apiSearchMDHandler)
 	r.Post("/api/search", apiSearchHandler)
 	r.Get("/api/documents", apiDocumentsHandler)
 	r.Get("/api/processing", apiProcessingHandler)
@@ -372,6 +373,77 @@ func apiSearchHandler(w http.ResponseWriter, r *http.Request) {
 	renderPartial(w, "document-list", docs)
 }
 
+// apiSearchMDHandler handles GET /api/search?q={query}&format=md
+// Returns all matching documents as concatenated plain-text markdown,
+// one document per section separated by ---. Intended for AI/LLM consumption.
+func apiSearchMDHandler(w http.ResponseWriter, r *http.Request) {
+	query := r.URL.Query().Get("q")
+	format := r.URL.Query().Get("format")
+
+	// Only serve markdown format; anything else falls back to a 400
+	if format != "md" {
+		http.Error(w, "format=md required", http.StatusBadRequest)
+		return
+	}
+	if query == "" {
+		http.Error(w, "q parameter required", http.StatusBadRequest)
+		return
+	}
+
+	docs, err := SearchDocuments(query, 200)
+	if err != nil {
+		docs, _ = SearchDocumentsFallback(query, 200)
+	}
+
+	w.Header().Set("Content-Type", "text/markdown; charset=utf-8")
+
+	if len(docs) == 0 {
+		w.Write([]byte("No documents found matching: " + query + "\n"))
+		return
+	}
+
+	var sb strings.Builder
+	for i, doc := range docs {
+		sb.WriteString("# Document: ")
+		if doc.Title != "" {
+			sb.WriteString(doc.Title)
+		} else {
+			sb.WriteString("(untitled)")
+		}
+		sb.WriteString("\n")
+		sb.WriteString("ID: ")
+		sb.WriteString(doc.ID)
+		if doc.Category != "" {
+			sb.WriteString(" | Category: ")
+			sb.WriteString(doc.Category)
+		}
+		if doc.Date != "" {
+			sb.WriteString(" | Date: ")
+			sb.WriteString(doc.Date)
+		}
+		if doc.Vendor != "" {
+			sb.WriteString(" | Vendor: ")
+			sb.WriteString(doc.Vendor)
+		}
+		sb.WriteString("\n\n")
+
+		text := doc.FullText
+		if text == "" {
+			text = doc.Summary
+		}
+		if text != "" {
+			sb.WriteString(text)
+			sb.WriteString("\n")
+		}
+
+		if i < len(docs)-1 {
+			sb.WriteString("\n---\n\n")
+		}
+	}
+
+	w.Write([]byte(sb.String()))
+}
+
 func apiProcessingHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(GetActiveJobs())