fix: correct misplaced parens in generated regen formula defaults (regen was silently 0)

[baughj]

Problem

HP/MP regen has been silently zero for any world whose config omits a Formulas
section — which includes ceridwen, whose xml/serverconfigs/config.xml contains no
Formula elements at all, so the hardcoded C# defaults are in use.

src/Objects/ServerFormulas.cs is <auto-generated> by Xsd2Code++ and had drifted
from the XSD:

Min( MAXHP * (0.1 + Max(CON, CON-LVL) * 0.01, MAXHP * 0.20) )
             ^ this paren should close after * 0.01

Min() therefore received a single argument. NCalc throws
NCalcEvaluationException: Min() takes exactly 2 arguments; Hybrasyl's
FormulaParser.Eval catches all exceptions and returns 0.0; World.cs casts that
to (uint) — so regen is 0.

How the drift happened

• a5759ab fixed the parens in both the XSD and ServerFormulas.cs, but to the
  wrong parenthesization (Min still got one argument).
• 5a1a080 ("fix misplaced parens in HpRegenPerTick/MpRegenPerTick formulas")
  corrected the XSD only — ServerFormulas.cs was never regenerated.

So the XSD has been right since April and the generated C# has been wrong since.

Fix

Regenerate-equivalent hand-patch of the two literals to match the XSD. The XSD is
unchanged and already correct, so a future Xsd2Code++ run will now agree with this
file.

Verification

• Both C# literals confirmed byte-identical to their XSD default= attributes by
  extracting and comparing them programmatically (not by eye — an eyeballed paren in a
  wrapped string literal is how this was introduced).
• Defaults extracted from the patched file and evaluated through NCalcSync 6.3.1
  using FormulaParser.Eval's semantics, for a level-10 character with CON/WIS 30 and
  1000 max HP/MP:

[PASS] _mpRegenPerTick          = 200      (was: throws -> 0)
[PASS] _hpRegenPerTick          = 200      (was: throws -> 0)
[PASS] _xpToNextLevel           = 250000
[PASS] _hpGainPerLevel          = 161.36
[PASS] _allowedCarryWeight      = 100.5
[PASS] _allowedEquipmentWeight  = 50.25

• dotnet build across all four TFMs: 0 Error(s).

Behaviour change — please read

This restores a cap that has not been functioning. With correct parens the Min binds
at CON >= 10, so HP regen becomes a flat 20% of max HP per tick for essentially
any character. That is exactly what the XSD specifies, but since regen has effectively
been 0, the swing is large and worth a balance look before this reaches players.

Release note

Package version bumped 0.9.6 → 0.9.7. Publishing is triggered by pushing a v*
tag (or manual workflow_dispatch), not by merging this PR — the package won't
exist on nuget.org until tagged. hybrasyl-server pins Hybrasyl.Xml at 0.9.6 via
PackageReference, so it will not pick this up until the tag is pushed and the
reference bumped (or it is built with UseLocalXml=true).

Context

Found while investigating a claim that NCalc truncates integer division. That claim was
measured false — 25 / 100 → 0.25 [Double] on 6.3.1, 5.8.0, and master — and the
regen symptom traced entirely to these parens. Full write-up in comhaigne
(docs/plans/hybrasyl-server/ncalc-integer-division.md).

Generated with Imbas imbas@eris.co

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.24%. Comparing base (8953d25) to head (6e2d3ca).

Additional details and impacted files

@@           Coverage Diff           @@
##             main       #5   +/-   ##
=======================================
  Coverage   61.24%   61.24%           
=======================================
  Files          40       40           
  Lines        1538     1538           
  Branches      350      350           
=======================================
  Hits          942      942           
  Misses        475      475           
  Partials      121      121           

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