feat(core): add HTTP QUERY method support

Adds the QUERY method (RFC 10008) — safe and idempotent like GET,
but carries a request body like POST, useful for complex filters
that don't fit in a URL query string.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

flash/src/test/java/dev/relism/flash/RequestParserTest.java

@@ -75,6 +75,16 @@ class RequestParserTest {
         assertEquals(body, new String(r.body().bytes(), StandardCharsets.UTF_8));
     }
 
+    @Test
+    void body_parsed_forQueryMethod() throws IOException {
+        String body = "{\"filter\":\"active\"}";
+        String raw  = "QUERY / HTTP/1.1\r\nContent-Type: application/json\r\nContent-Length: " + body.length() + "\r\n\r\n" + body;
+        Request r   = new RequestParser().parse(new ByteArrayInputStream(raw.getBytes(StandardCharsets.UTF_8)));
+        assertNotNull(r);
+        assertEquals(dev.relism.flash.http.HttpMethod.QUERY, r.method());
+        assertEquals(body, new String(r.body().bytes(), StandardCharsets.UTF_8));
+    }
+
     @Test
     void body_emptyWhenNoContentLength() throws IOException {
         Request r = parse(req("GET / HTTP/1.1", "Host: localhost"));

flash/src/test/java/dev/relism/flash/http/HttpMethodTest.java

@@ -34,6 +34,7 @@ class HttpMethodTest {
         assertEquals(HttpMethod.TRACE,   parse("TRACE"));
         assertEquals(HttpMethod.CONNECT, parse("CONNECT"));
         assertEquals(HttpMethod.PURGE,   parse("PURGE"));
+        assertEquals(HttpMethod.QUERY,   parse("QUERY"));
     }
 
     @Test