fix(security): stream tickets instead of session tokens in URLs (FLAW-22)

WebSocket and EventSource put the 30-day session token into the URL,
where proxies log it. The app now gets a one-time ticket right before
connecting (POST /auth/stream-ticket, 60 s, bound to the token version);
?token= is no longer accepted for streams, non-browser clients may use
the Authorization header.

With BASE_URL set, CORS allows only that origin and WebSocket upgrades
only it or the requested host; credentials are off (no cookies exist).
Logout, ending all sessions, a new password and deactivation close all
live streams of the account; clients with a valid session reconnect
with a fresh ticket.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/streamticket_test.go

@@ -0,0 +1,73 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/sandrodach/mindsift/internal/config"
+)
+
+func TestStreamTicketsReplaceTokensInURLs(t *testing.T) {
+	srv, store, token := setupTestServer(t)
+	router := srv.Router()
+	ticket := func(tok string) string {
+		req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/stream-ticket", nil)
+		req.Header.Set("Authorization", "Bearer "+tok)
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+		var out struct{ Ticket string }
+		_ = json.Unmarshal(rec.Body.Bytes(), &out)
+		return out.Ticket
+	}
+	stream := func(query string) string {
+		return srv.authenticateUserFromReq(httptest.NewRequest(http.MethodGet, "/api/v1/events?"+query, nil))
+	}
+
+	tk := ticket(token)
+	if tk == "" {
+		t.Fatal("no ticket issued")
+	}
+	if stream("ticket="+tk) == "" {
+		t.Fatal("a fresh ticket must open the stream")
+	}
+	if stream("ticket="+tk) != "" {
+		t.Fatal("a ticket works only once")
+	}
+	if stream("token="+token) != "" {
+		t.Fatal("session tokens in the URL are no longer accepted")
+	}
+
+	// Ending all sessions makes unused tickets worthless as well
+	tk = ticket(token)
+	uid := stream("ticket=" + ticket(token))
+	_ = store.RevokeAllUserTokens(uid)
+	if stream("ticket="+tk) != "" {
+		t.Fatal("ticket from before 'all sessions ended' must be refused")
+	}
+}
+
+func TestStreamOriginCheck(t *testing.T) {
+	srv := &Server{cfg: &config.Config{BaseURL: "https://notes.example.com", BaseURLSet: true}}
+	check := func(host, origin string) bool {
+		r := httptest.NewRequest(http.MethodGet, "/api/v1/ws", nil)
+		r.Host = host
+		if origin != "" {
+			r.Header.Set("Origin", origin)
+		}
+		return srv.streamOriginAllowed(r)
+	}
+	if !check("mindsift:8080", "https://notes.example.com") {
+		t.Error("BASE_URL origin must pass even if the proxy rewrote Host")
+	}
+	if !check("notes.example.com", "https://notes.example.com") {
+		t.Error("same host must pass")
+	}
+	if check("notes.example.com", "https://evil.example.org") {
+		t.Error("foreign origin must be refused")
+	}
+	if !check("notes.example.com", "") {
+		t.Error("non-browser clients without Origin pass (they still need a ticket)")
+	}
+}