Add PE section enumeration and section views (section-local / RVA / absolute)

vmie_win32_sections lists a module's PE sections (name, RVA, virtual size,
VR_* protection) for any image base in a process address space - including a
base found by scanning, not only loader-list modules. vmie_win32_section_view
gathers a section's bytes into a caller buffer and returns a mem_view_t whose
base_va is chosen by view_base: SECTION_LOCAL (0, section-relative offsets),
MODULE_RVA (ASLR-stable module RVAs), or ABSOLUTE_VA (live VA). Because the pure
scanners report base_va + offset, the mode directly selects the coordinate space
of every hit - feeding a view to sig_all or x86_decode yields section-relative,
RVA, or absolute results with no extra work.

The MZ/PE header walk is factored into one helper that both pe_find_section and
the new enumerator share - no second parser. The whole public surface is
documented with the operational nuances (coordinate stability, borrowed-buffer
lifetime, truncation, residency) and worked examples.

src/engine/include/pe.h

@@ -14,6 +14,23 @@
 #include <stdbool.h>
 #include "memmodel.h"   /* mem_view_t, vmie_mem */
 
+/* One enumerated PE section header, decoded by pe_sections. Mirrors the public
+ * win32 section_desc, but stays engine-private (this header is engine-only).
+ *   name  - section name, NUL-terminated (PE names are <= 8 bytes; name[8] NUL)
+ *   rva   - section RVA (relative to module_base)
+ *   vsize - virtual size in bytes
+ *   prot  - VR_R/VR_W/VR_X from the section Characteristics (VR_U never set) */
+typedef struct { char name[9]; uint32_t rva; uint32_t vsize; uint32_t prot; } pe_secrec;
+
+/* Enumerate the section headers of the PE image based at `module_base` inside a
+ * view holding at least the image headers (the first page is enough).
+ *   out, max - caller array receiving up to `max` pe_secrec; out may be NULL to
+ *              count only. Headers truncated by the view end are not reported.
+ * Returns the TOTAL section count (may exceed `max`), or -1 if `v` does not hold
+ * a parseable PE at `module_base`. Shares the section-table walk with
+ * pe_find_section (one header parser, no duplication). */
+int pe_sections(mem_view_t v, uint64_t module_base, pe_secrec* out, int max);
+
 /* Locate a PE section by name within a view that contains at least the image
  * headers at `module_base` (the first page is enough).
  *   module_base - image base VA, must be >= v.base_va and inside `v`