Add recursion depth limit to prevent stack overflow in hash function

[Copilot]

The recursive _update_hash_for_value function could cause stack overflow when hashing deeply nested data structures (lists, dicts, tuples).

Changes

• Added depth tracking: _update_hash_for_value now tracks recursion depth and enforces a configurable limit (default: 100 levels)
• Clear error handling: Raises RecursionError with actionable guidance when limit is exceeded
• Comprehensive tests: Added tests/test_recursion_depth.py covering edge cases for lists, dicts, and tuples at various nesting levels

Behavior

Normal nested structures continue to work:

# 50 levels deep - works fine
nested = []
current = nested
for _ in range(50):
    inner = []
    current.append(inner)
    current = inner

@cachier()
def process(data):
    return "ok"

process(nested)  # ✓ Cached successfully

Pathological cases now fail fast with clear guidance:

# 150 levels deep - raises RecursionError
nested = []
current = nested
for _ in range(150):
    inner = []
    current.append(inner)
    current = inner

process(nested)
# RecursionError: Maximum recursion depth (100) exceeded while hashing nested 
# data structure. Consider flattening your data or using a custom hash_func parameter.

The implementation is backward compatible - new parameters use defaults that preserve existing behavior for typical use cases.

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