fix(compression): raise decompression ceiling to the protocol whole-file limit

MAX_DECOMPRESSED_SIZE was 100 MiB while the receiver advertises and the
sender compresses whole files up to MAX_RECEIVE_WHOLE_FILE_SIZE (256 MiB),
so -z on a 100-256 MiB regular file failed with 'Declared decompressed
size exceeds 104857600 bytes'.  Define the internal bomb-guard ceiling in
terms of the protocol constant so the two bounds cannot drift, and add
unit coverage for a 130 MiB payload (accepted) and an over-ceiling
declared size (still rejected).

src/shared/compression.c

@@ -16,7 +16,14 @@
 #include <zstd.h>
 
 #define INITIAL_DECOMPRESS_BUF_SIZE (1024 * 1024)
-#define MAX_DECOMPRESSED_SIZE (100ULL * 1024 * 1024) /* 100 MB hard ceiling */
+
+/* Hard ceiling for a single decompression.  The sender compresses whole files
+ * up to the protocol's whole-file receive bound, so the decompressor must
+ * accept payloads that large; referencing the protocol constant keeps the two
+ * bounds from drifting apart (they previously did: a 100 MB ceiling rejected
+ * 100-256 MB files).  This remains a real bomb guard -- every allocation in the
+ * paths below is clamped to it -- so it must not exceed the protocol bound. */
+#define MAX_DECOMPRESSED_SIZE MAX_RECEIVE_WHOLE_FILE_SIZE
 
 /* rsync 3.4.1's built-in skip-compress suffix list (the `--skip-compress`
  * defaults, in the man page's order).  rsync stores it as space-separated