Use Animator.StringToHash for repeated Animator method calls

[Copilot]

Partially fixes #49

Checklist

• I have read the Contribution Guide ;
• There is an approved issue describing the change when contributing a new analyzer or suppressor ;
• I have added tests that prove my fix is effective or that my feature works ;
• I have added necessary documentation (if appropriate) ;

Short description of what this resolves:

Implements analyzer UNT0041 to detect Animator method calls with string literals that have int (hash) overloads, suggesting performance optimization via Animator.StringToHash.

Changes proposed in this pull request:

• Analyzer: Detects Animator methods (Play, SetBool, SetTrigger, GetFloat, etc.) called with string literals when int overload exists
• Code Fix: Extracts string literal to private static readonly int field initialized with Animator.StringToHash(), replaces call site with field reference
• Field Naming: Generates PascalCase field names from literal values (e.g., "Attack" → AttackHash, "Attack-Heavy 01" → AttackHeavy01Hash)
• Deduplication: Reuses existing hash fields when present, avoiding duplicates
• Tests: 14 test cases covering common scenarios, edge cases with special characters, and validation that non-Animator types and variables aren't flagged
• Documentation: Added UNT0041.md with rationale and examples

Example:

// Before
_animator.Play("Attack");
_animator.SetBool("IsRunning", true);

// After applying fix
private static readonly int AttackHash = Animator.StringToHash("Attack");
private static readonly int IsRunningHash = Animator.StringToHash("IsRunning");

_animator.Play(AttackHash);
_animator.SetBool(IsRunningHash, true);

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