bootloader: rebase onto upstream 1.0.0, sync firmware-loader version

Bootloader fork rebase:
- Base changed from 0.1.0 pre-patched archive to upstream 1.0.0 tag (c7eeb9f)
- Applied 0001-redbear-local-forks.patch (Cargo.toml crate path redirects)
- Applied fix-uefi-alloc-panic.patch equivalents (4 panic!() -> graceful
  error handling in src/main.rs)
- Applied P5-live-preload-cap-1gib.patch (1 GiB cap on live image preload)
- Skipped: P0 GPT partition scan (requires new module + integration),
  P1 timeout/default-resolution, P2 live preload guard (subsumed by
  panic fixes + cap), P3 live image safe read, P4 large ISO boot,
  redox.patch — to be applied in dedicated rebase session.

firmware-loader/Cargo.toml: version 0.1.0 -> 0.3.0 (sync with other
Red Bear custom crates which are at 0.3.0).

fork-upstream-map.toml: bootloader back from PENDING_REBASE to 1.0.0
since the partial rebase matches upstream 1.0.0 content.

fork-upstream-map.toml: base restored to 'main' tracked (was correctly
tracked by build-redbear.sh).

local/recipes/tools/diffutils/source/gnulib-tests/test-reallocarray.c

@@ -0,0 +1,64 @@
+/* Test of reallocarray function.
+   Copyright (C) 2010-2025 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdlib.h>
+
+#include <errno.h>
+#include <stdint.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (reallocarray, void *, (void *, size_t, size_t));
+
+#include "macros.h"
+
+/* Work around clang bug
+   <https://github.com/llvm/llvm-project/issues/114772>.  */
+void *(*volatile my_reallocarray) (void *, size_t, size_t) = reallocarray;
+#undef reallocarray
+#define reallocarray my_reallocarray
+
+int
+main ()
+{
+  /* Check that reallocarray fails when requested to allocate a block
+     of memory larger than PTRDIFF_MAX or SIZE_MAX bytes.  */
+  for (size_t n = 2; n != 0; n <<= 1)
+    {
+      void *p = NULL;
+
+      if (PTRDIFF_MAX / n + 1 <= SIZE_MAX)
+        {
+          p = reallocarray (p, PTRDIFF_MAX / n + 1, n);
+          ASSERT (p == NULL);
+          ASSERT (errno == ENOMEM);
+        }
+
+      p = reallocarray (p, SIZE_MAX / n + 1, n);
+      ASSERT (p == NULL);
+      ASSERT (errno == ENOMEM
+              || errno == EOVERFLOW /* NetBSD */);
+
+      /* Reallocarray should not crash with zero sizes.  */
+      p = reallocarray (p, 0, n);
+      p = reallocarray (p, n, 0);
+      free (p);
+    }
+
+  return test_exit_status;
+}