Add -CSVersion so profiles load on Cobalt Strike 4.13 (second half of #32)

[warpedatom]

This is the second half of #32, and it builds on #30, so it wants merging
after that one. #30 fixes two of the four reasons c2lint rejects every
generated profile on Cobalt Strike 4.13; this fixes the other two. Because the
branch is cut from #30, the diff here includes those commits until #30 lands.

The problem

Cobalt Strike 4.13 no longer accepts two of the stage options SourcePoint
emits, so no generated profile can be loaded on the current release:

Error: invalid option for <.stage> at line 68
       rdll_loader
Error: invalid option for <.stage> at line 77
       name

I isolated every stage option SourcePoint writes, one per minimal profile, to
confirm exactly which ones 4.13 rejects:

option	4.13
set rdll_loader "PrependLoader"	rejected
set rdll_loader "StompLoader"	rejected
set name "test.dll"	rejected
set checksum "123"	accepted
set rich_header "\x00"	accepted
set copy_pe_header "false"	accepted
set eaf_bypass "false"	accepted
set rdll_use_syscalls "false"	accepted
set syscall_method "None"	accepted

rdll_loader is rejected on both values, so this is not the stomp loader
deprecation from an earlier release. And checksum and rich_header still
work while name does not, so PE cloning survives in 4.13, it just no longer
takes the cloned module's name.

The approach

I did not want to simply delete the two options, since that would quietly
degrade anyone still on an older team server: name appears in all 30
Peclone_list entries, and rdll_loader backs the documented -RdllLoader
flag.

So -CSVersion selects the target release. 4.13 and newer omit both options;
4.12 and older emit them exactly as before. It defaults to 4.13, on the
grounds that a tool should work against the current release out of the box, but
that default is a one-word change in Loader/CSVersion.go if you would rather
not alter behaviour for existing users.

$ ./SourcePoint -Host acme-email.com -Outfile p.profile -Profile 2
...
[!] Targeting Cobalt Strike 4.13: stage.rdll_loader and stage.name omitted, both removed in 4.13

The omission is reported rather than silent, so nobody wonders where their
-RdllLoader setting went. -RdllLoader is still validated regardless of
target, so a typo remains an error instead of being discarded along with the
directive.

A third incompatibility, same shape

With rdll_loader and name handled, c2lint gets further and rejects the PE
clone image sizes:

[-] .stage.image_size_x86 must be larger than 372736 bytes
[-] .stage.image_size_x64 must be larger than 462848 bytes

Cobalt Strike requires each to be at least the size of the Beacon DLL it stomps
into the image. The values in Peclone_list are the real sizes of the modules
being mimicked, and the Beacon has outgrown most of them, so on 4.13 only four
of the thirty clone entries produce a loadable profile: the four that happen to
carry no image_size directives at all.

Raising them to a fixed floor would age out again with the next Beacon growth,
so 4.13 and newer omit them and let Cobalt Strike size the image. The four
entries that already ship without them are the evidence that works.

One fix that falls out of this

The set name directive lives inside the Peclone_list entries, and the
"Beacon DLL Spoofed To:" summary line recovered the module name by splitting
the clone block on ; and indexing len-3. That arithmetic breaks as soon as
the block loses a directive, so the name is now read with a regex before the
directive is stripped. Four of the thirty entries also turn out to carry no
image_size directives, which the old index maths happened to survive and the
new code does not care about either way.

Verification

Against a licensed Cobalt Strike 4.13 team server:

• a profile generated with the defaults loads into the team server, not
  just past c2lint: [+] I see you're into threat replication. loaded. and
  [+] Team server is up. The only remaining c2lint warning is the absent
  code-signing keystore.
• that was with -PE_Clone 4, one of the twenty-six entries that fails without
  the image_size change, and with -DNS and -Stage true both on
• generating a profile for all thirty clone entries leaves no image_size or
  name directive anywhere
• a profile generated with -CSVersion 4.12 still fails on 4.13 with the
  stage errors, confirming the gate actually gates
• -CSVersion nonsense is rejected up front

Tests cover version parsing and comparison, reading the module name out of
every Peclone_list entry, stripping removing the name directive and nothing
else, and set pipename / set ssh_pipename not being mistaken for set name.

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