Modernize build: switch to CMake, add unit tests, fix man pages

Remove autotools (configure.ac, Makefile.am, m4/, autogen.sh) and make
CMake the sole build system. Enhance CMake with proper Find modules for
MbedTLS, libsodium, PCRE, and c-ares with version/feature detection.
Add support for connmarktos, nftables, stack protector, and MinGW.

Add 10 unit test suites (CTest) covering base64, buffer, cache, crypto,
jconf, json, netutils, ppbloom, rule, and utils modules. Add a Python
stress test measuring bandwidth per cipher with memory leak detection.

Fix man page typos ("Resovle" -> "Resolve"), document missing TCP buffer
options, fix ss-manager duplicate --executable entry, add example section
to ss-tunnel, and document --workdir and --nftables-sets options.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_buffer.c

@@ -0,0 +1,103 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+
+int verbose = 0;
+
+#include "crypto.h"
+
+/* Provide nonce_cache symbol needed by crypto.c */
+struct cache *nonce_cache = NULL;
+
+static void
+test_balloc(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    int ret = balloc(&buf, 100);
+    assert(ret == 0);
+    (void)ret;
+    assert(buf.data != NULL);
+    assert(buf.capacity >= 100);
+    assert(buf.len == 0);
+    assert(buf.idx == 0);
+
+    bfree(&buf);
+    assert(buf.data == NULL);
+    assert(buf.capacity == 0);
+}
+
+static void
+test_brealloc(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    balloc(&buf, 50);
+    buf.len = 10;
+
+    /* Grow the buffer */
+    int ret = brealloc(&buf, 10, 200);
+    assert(ret == 0);
+    (void)ret;
+    assert(buf.capacity >= 200);
+    assert(buf.len == 10);
+
+    bfree(&buf);
+}
+
+static void
+test_bprepend(void)
+{
+    buffer_t dst, src;
+    memset(&dst, 0, sizeof(dst));
+    memset(&src, 0, sizeof(src));
+
+    balloc(&dst, 100);
+    balloc(&src, 100);
+
+    /* Put some data in src */
+    memcpy(src.data, "HEADER", 6);
+    src.len = 6;
+
+    /* Put some data in dst */
+    memcpy(dst.data, "BODY", 4);
+    dst.len = 4;
+
+    int ret = bprepend(&dst, &src, 200);
+    assert(ret == 0);
+    (void)ret;
+    assert(dst.len == 10);
+    assert(memcmp(dst.data, "HEADERBODY", 10) == 0);
+
+    bfree(&dst);
+    bfree(&src);
+}
+
+static void
+test_balloc_zero(void)
+{
+    buffer_t buf;
+    memset(&buf, 0, sizeof(buf));
+
+    int ret = balloc(&buf, 0);
+    assert(ret == 0);
+    (void)ret;
+    /* A zero-capacity buffer should still succeed */
+    bfree(&buf);
+}
+
+int
+main(void)
+{
+    test_balloc();
+    test_brealloc();
+    test_bprepend();
+    test_balloc_zero();
+    return 0;
+}