Phase 6: rules editor + unsubscribe detection (AUD-72)

- FR-11 rules editor: plain-text area at /rules, saved and versioned
  (SaveRules appends a version; restore re-saves an old version), parse
  errors surfaced, one-click re-classify. The reply model now reads the
  rules document too (FR-11).
- FR-7 unsubscribe: parse and store List-Unsubscribe / List-Unsubscribe-Post
  (migration v6), detect email and web links (internal/unsubscribe), a
  domain-level ignore list, and an explicit record of what was marked. No
  code path contacts an unsubscribe link; acting on one needs Sam's approval.
- Migration v6 is additive; unsubscribe gains url/updated_at.
- Tests: detector, parser, store migration/records/candidates, rules editor,
  unsubscribe handlers, message-detail rendering.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

internal/mailfetch/fetch.go

@@ -102,18 +102,20 @@ func (f *Fetcher) Fetch(ctx context.Context) (Summary, error) {
 			headersSeen[parsed.SourceHeader] = struct{}{}
 		}
 		msg := &store.Message{
-			GmailID:         gmailID(r, uidValidity),
-			ThreadID:        r.GmailThreadID,
-			MessageIDHeader: parsed.MessageID,
-			FromAddr:        parsed.From,
-			ToAddr:          parsed.To,
-			Subject:         parsed.Subject,
-			BodyText:        parsed.BodyText,
-			SourceAddress:   parsed.SourceAddress,
-			DateSent:        parsed.Date,
-			ReceivedAt:      now,
-			IMAPUID:         int64(r.UID),
-			IMAPUIDValidity: int64(uidValidity),
+			GmailID:             gmailID(r, uidValidity),
+			ThreadID:            r.GmailThreadID,
+			MessageIDHeader:     parsed.MessageID,
+			FromAddr:            parsed.From,
+			ToAddr:              parsed.To,
+			Subject:             parsed.Subject,
+			BodyText:            parsed.BodyText,
+			SourceAddress:       parsed.SourceAddress,
+			ListUnsubscribe:     parsed.ListUnsubscribe,
+			ListUnsubscribePost: parsed.ListUnsubscribePost,
+			DateSent:            parsed.Date,
+			ReceivedAt:          now,
+			IMAPUID:             int64(r.UID),
+			IMAPUIDValidity:     int64(uidValidity),
 		}
 		if _, err := f.store.UpsertMessage(ctx, msg); err != nil {
 			return sum, err

internal/mailfetch/message.go

@@ -27,8 +27,13 @@ type ParsedMessage struct {
 	Date    time.Time
 	// MessageID is the RFC822 Message-ID header, used for reply threading
 	// (Phase 5, FR-8).
-	MessageID     string
-	SourceAddress string
+	MessageID string
+	// ListUnsubscribe and ListUnsubscribePost are the RFC 2369/8058 headers that
+	// name the unsubscribe targets (Phase 6, FR-7). They are stored raw so the
+	// detector can run later without a refetch.
+	ListUnsubscribe     string
+	ListUnsubscribePost string
+	SourceAddress       string
 	// SourceHeader records which header the source address came from, so FR-2
 	// decisions are auditable.
 	SourceHeader string
@@ -43,11 +48,13 @@ func ParseMessage(raw []byte) (*ParsedMessage, error) {
 	}
 	h := msg.Header
 	pm := &ParsedMessage{
-		From:      decodeHeader(h.Get("From")),
-		To:        decodeHeader(h.Get("To")),
-		Subject:   decodeHeader(h.Get("Subject")),
-		Date:      parseDate(h.Get("Date")),
-		MessageID: strings.TrimSpace(h.Get("Message-Id")),
+		From:                decodeHeader(h.Get("From")),
+		To:                  decodeHeader(h.Get("To")),
+		Subject:             decodeHeader(h.Get("Subject")),
+		Date:                parseDate(h.Get("Date")),
+		MessageID:           strings.TrimSpace(h.Get("Message-Id")),
+		ListUnsubscribe:     strings.TrimSpace(h.Get("List-Unsubscribe")),
+		ListUnsubscribePost: strings.TrimSpace(h.Get("List-Unsubscribe-Post")),
 	}
 	pm.SourceAddress, pm.SourceHeader = SourceAddress(textproto.MIMEHeader(h))
 	pm.BodyText = extractBody(textproto.MIMEHeader(h), msg.Body)

internal/mailfetch/message_test.go

@@ -172,3 +172,34 @@ func TestHeaderAddressParsing(t *testing.T) {
 		}
 	}
 }
+
+func TestParseMessageCapturesUnsubscribeHeaders(t *testing.T) {
+	raw := "From: Heritage Fruit Trees <support@heritagefruittrees.com.au>\r\n" +
+		"To: samuelrolfe@gmail.com\r\n" +
+		"X-Pm-Original-To: hello@where-woof.com\r\n" +
+		"Subject: New workshops\r\n" +
+		"List-Unsubscribe: <mailto:unsub@heritagefruittrees.com.au?subject=unsubscribe>, <https://heritagefruittrees.com.au/u?id=1>\r\n" +
+		"List-Unsubscribe-Post: List-Unsubscribe=One-Click\r\n" +
+		"Message-Id: <abc@mail.example>\r\n" +
+		"Date: Mon, 01 Jan 2026 10:00:00 +0000\r\n" +
+		"Content-Type: text/plain; charset=utf-8\r\n" +
+		"\r\n" +
+		"Hello, you can unsubscribe at https://heritagefruittrees.com.au/u?id=1.\r\n"
+
+	pm, err := ParseMessage([]byte(raw))
+	if err != nil {
+		t.Fatalf("ParseMessage() error = %v", err)
+	}
+	if !strings.Contains(pm.ListUnsubscribe, "mailto:unsub@heritagefruittrees.com.au") {
+		t.Errorf("ListUnsubscribe = %q", pm.ListUnsubscribe)
+	}
+	if !strings.Contains(pm.ListUnsubscribe, "https://heritagefruittrees.com.au/u?id=1") {
+		t.Errorf("ListUnsubscribe = %q", pm.ListUnsubscribe)
+	}
+	if pm.ListUnsubscribePost != "List-Unsubscribe=One-Click" {
+		t.Errorf("ListUnsubscribePost = %q", pm.ListUnsubscribePost)
+	}
+	if pm.SourceAddress != "hello@where-woof.com" {
+		t.Errorf("SourceAddress = %q", pm.SourceAddress)
+	}
+}