* fix(targets): keep original DOS padding out of e_lfanew
A complete DOS header with a nonempty relocation table that ended before
e_lfanew treated the padding dword at 0x3c as a Windows declaration. Without
a recognized Windows signature, fall back to the validated DOS structure so
original DOS images are not refused as malformed Windows targets. Preserve
unresolved-candidate handling when no relocation table delimits the padding.
* test(ghidra): cover DOS padding and unresolved header candidates
* fix(targets): read Windows signatures before dismissing DOS padding
* docs(targets): reconcile DOS padding admission contract
Document that relocation-table padding inside a complete DOS header is DOS data, while an unread Windows signature beyond the current probe is requested before that rule applies.
Aligns docs/installation.md with docs/ghidra-dos.md after the MZ admission fix.
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Co-authored-by: dhruvac29 <dhruvac29@users.noreply.github.com>
