Phase 2 (partial): Dirty Pipe DETECT-ONLY module + core/kernel_range

- core/kernel_range.{c,h}: branch-aware patched-version comparison.
  Every future module needs 'is the host kernel in the affected
  range?'; centralized here. Models stable-branch backports
  (e.g. 5.10.102, 5.15.25) so a 5.15.20 host correctly reports
  VULNERABLE while a 5.15.50 host reports OK.

- modules/dirty_pipe_cve_2022_0847/ (promoted out of _stubs):
  - iamroot_modules.{c,h}: dirty_pipe module exposing detect() that
    parses /proc/version and compares against the four known patched
    branches (5.10.102, 5.15.25, 5.16.11, 5.17+ inherited). Returns
    IAMROOT_OK / IAMROOT_VULNERABLE / IAMROOT_TEST_ERROR with stderr
    hints in human-readable scan mode.
  - exploit() returns IAMROOT_PRECOND_FAIL with a 'not yet
    implemented' message; landing the actual exploit needs Phase 1.5
    extraction of passwd/su helpers into core/.
  - detect/auditd.rules: splice() syscall + passwd/shadow file watches
  - detect/sigma.yml: non-root modification of /etc/passwd|shadow|sudoers

- iamroot.c main() calls iamroot_register_dirty_pipe() alongside
  the copy_fail_family registration.

- Makefile gains the dirty_pipe family as a separate object set.

Verified end-to-end on kctf-mgr (kernel 6.12.86): build clean, 6
modules in --list, --scan correctly reports dirty_pipe as patched,
JSON output ingest-ready.

Makefile

@@ -20,8 +20,8 @@ BUILD   := build
 BIN     := iamroot
 
 # core/
-CORE_SRC := core/registry.c
-CORE_OBJ := $(BUILD)/core/registry.o
+CORE_SRCS := core/registry.c core/kernel_range.c
+CORE_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(CORE_SRCS))
 
 # Family: copy_fail_family
 # All DIRTYFAIL .c files contribute; iamroot_modules.c is the bridge.
@@ -31,10 +31,15 @@ CFF_SRCS := $(wildcard $(CFF_DIR)/src/*.c) $(CFF_DIR)/iamroot_modules.c
 CFF_SRCS := $(filter-out $(CFF_DIR)/src/dirtyfail.c, $(CFF_SRCS))
 CFF_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(CFF_SRCS))
 
+# Family: dirty_pipe (single-CVE family, no shared infrastructure)
+DP_DIR   := modules/dirty_pipe_cve_2022_0847
+DP_SRCS  := $(DP_DIR)/iamroot_modules.c
+DP_OBJS  := $(patsubst %.c,$(BUILD)/%.o,$(DP_SRCS))
+
 # Top-level dispatcher
 TOP_OBJ  := $(BUILD)/iamroot.o
 
-ALL_OBJS := $(TOP_OBJ) $(CORE_OBJ) $(CFF_OBJS)
+ALL_OBJS := $(TOP_OBJ) $(CORE_OBJS) $(CFF_OBJS) $(DP_OBJS)
 
 .PHONY: all clean debug static help