Add rspamd symbol descriptions from embedded/API lookup

Embed rspamd-symbols.json in the binary to provide human-readable
descriptions for rspamd symbols in reports. Optionally fetch fresh
symbols from a configurable rspamd API URL (--rspamd-api-url flag),
falling back to the embedded list on error. Update the frontend to
display descriptions alongside symbol names and scores.

pkg/analyzer/rspamd_symbols.go

@@ -0,0 +1,105 @@
+// This file is part of the happyDeliver (R) project.
+// Copyright (c) 2026 happyDomain
+// Authors: Pierre-Olivier Mercier, et al.
+//
+// This program is offered under a commercial and under the AGPL license.
+// For commercial licensing, contact us at <contact@happydomain.org>.
+//
+// For AGPL licensing:
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package analyzer
+
+import (
+	_ "embed"
+	"encoding/json"
+	"io"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+)
+
+//go:embed rspamd-symbols.json
+var embeddedRspamdSymbols []byte
+
+// rspamdSymbolGroup represents a group of rspamd symbols from the API/embedded JSON.
+type rspamdSymbolGroup struct {
+	Group string              `json:"group"`
+	Rules []rspamdSymbolEntry `json:"rules"`
+}
+
+// rspamdSymbolEntry represents a single rspamd symbol entry.
+type rspamdSymbolEntry struct {
+	Symbol      string  `json:"symbol"`
+	Description string  `json:"description"`
+	Weight      float64 `json:"weight"`
+}
+
+// parseRspamdSymbolsJSON parses the rspamd symbols JSON into a name->description map.
+func parseRspamdSymbolsJSON(data []byte) map[string]string {
+	var groups []rspamdSymbolGroup
+	if err := json.Unmarshal(data, &groups); err != nil {
+		log.Printf("Failed to parse rspamd symbols JSON: %v", err)
+		return nil
+	}
+
+	symbols := make(map[string]string, len(groups)*10)
+	for _, g := range groups {
+		for _, r := range g.Rules {
+			if r.Description != "" {
+				symbols[r.Symbol] = r.Description
+			}
+		}
+	}
+	return symbols
+}
+
+// LoadRspamdSymbols loads rspamd symbol descriptions.
+// If apiURL is non-empty, it fetches from the rspamd API first, falling back to the embedded list on error.
+func LoadRspamdSymbols(apiURL string) map[string]string {
+	if apiURL != "" {
+		if symbols := fetchRspamdSymbols(apiURL); symbols != nil {
+			return symbols
+		}
+		log.Printf("Failed to fetch rspamd symbols from %s, using embedded list", apiURL)
+	}
+	return parseRspamdSymbolsJSON(embeddedRspamdSymbols)
+}
+
+// fetchRspamdSymbols fetches symbol descriptions from the rspamd API.
+func fetchRspamdSymbols(apiURL string) map[string]string {
+	url := strings.TrimRight(apiURL, "/") + "/symbols"
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Get(url)
+	if err != nil {
+		log.Printf("Error fetching rspamd symbols: %v", err)
+		return nil
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		log.Printf("rspamd API returned status %d", resp.StatusCode)
+		return nil
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Printf("Error reading rspamd symbols response: %v", err)
+		return nil
+	}
+
+	return parseRspamdSymbolsJSON(body)
+}