feat(binary-layout): admit ELF32 i386, ARM and MIPS layout profiles (#7052)

* feat(binary-layout): admit ELF32 i386, ARM and MIPS layout profiles

inspect_binary_layout refused every ELF32 object, so router and IoT
firmware (ARM32, MIPS32) got no layout facts at all.

The pwntools adapter now admits EXEC/DYN/REL objects in these profiles:
ELF64 x86-64, ELF32 i386, ELF32 little-endian ARM and ELF32 little- or
big-endian MIPS. Header fields are read in the declared byte order, the
ELF32 header is bounds-checked at 52 bytes, and pwntools' own reported
architecture, class and byte order must match the admitted profile.
Other machines, classes and byte orders keep an unsupported_target
refusal that names the admitted profiles.

The output schema admits exactly those architecture combinations, and
the Evidence subject now names the reported machine instead of always
claiming x86_64.

verify:binary:layout cross-compiles i386, ARM, MIPS and MIPSel
executables and relocatable objects (never executed) and checks every
section name, address, offset and size against GNU readelf through CLI
and MCP. The real-binary-layout workflow installs those toolchains.

Refs #6934

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

* ci(binary-layout): install target libc headers for ELF32 fixtures

--no-install-recommends skips the libc6-dev-*-cross packages the cross
compilers only recommend, so the i686 fixture fell back to the host's
/usr/include and failed to find bits/libc-header-start.h. Install the
four target libc development packages explicitly.

Refs #6934

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

* fix(binary-layout): size the minimum symbol entry by ELF class

The relocation reference check required a 24-byte Elf64_Sym entry, so
every positive symbol reference in an ELF32 report was refused as
unreadable output. Elf32_Sym is 16 bytes; take the minimum from the
reported class. A 64-bit table with 16-byte entries is still refused.

Refs #6934

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

* test(binary-layout): compare ELF32 symbols and relocations with readelf

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>

src/application/binaryDiagnostics/BinaryLayoutService.test.ts

@@ -56,6 +56,28 @@ it("records the decoded layout once in its Evidence", async () => {
   expect(evidence.raw_result).toBeNull();
 });
 
+it.each([
+  [{ machine: "EM_X86_64", bits: 64, byte_order: "little" }, "x86_64"],
+  [{ machine: "EM_386", bits: 32, byte_order: "little" }, "x86"],
+  [{ machine: "EM_ARM", bits: 32, byte_order: "little" }, "arm"],
+  [{ machine: "EM_MIPS", bits: 32, byte_order: "big" }, "mips"],
+] as const)(
+  "names the reported %j machine in its Evidence subject",
+  async (architecture, expected) => {
+    const layout = { ...binaryLayoutFixture(), architecture };
+    const service = new BinaryLayoutService({
+      inspectAndClose(input, options) {
+        return this.inspect(input, options);
+      },
+      identity: BINARY_LAYOUT_TEST_PROVIDER,
+      inspect: () => Promise.resolve(ok(layout)),
+    });
+    const result = await service.inspect({ path: layout.artifact.path });
+    if (!result.ok) throw result.error;
+    expect(parseEvidence(result.value).subject?.architecture).toBe(expected);
+  },
+);
+
 it("preserves a provider's actionable unsupported reason", async () => {
   const failure = new AnalysisCapabilityUnavailableError(
     "fixture-layout",