Closes #5216: remove camelCase

[ajpotts]

Standardize Public API Naming & Add Deprecation Shims

Summary

This PR standardizes Arkouda’s public Python API to PEP 8–compliant snake_case naming, while preserving backward compatibility through explicit deprecation shims. The goal is to modernize the API surface, unblock stricter linting (Ruff N802), and provide a clear, low-risk migration path for users.

No user-facing functionality is removed in this PR.

---

Key Changes

1. Snake_case canonical APIs

The following camelCase public APIs have been replaced with snake_case equivalents and updated throughout the codebase:

Dtype / scalar helpers

• isSupportedInt → is_supported_int
• isSupportedFloat → is_supported_float
• isSupportedNumber → is_supported_number
• isSupportedBool → is_supported_bool
• isSupportedDType / isSupportedDtype → is_supported_dtype

Logger API

• getArkoudaLogger → get_arkouda_logger
• getArkoudaClientLogger → get_arkouda_client_logger
• enableVerbose → enable_verbose
• disableVerbose → disable_verbose
• ArkoudaLogger.changeLogLevel → change_log_level
• ArkoudaLogger.getHandler → get_handler

Client dtypes

• BitVectorizer → bit_vectorizer

Random (legacy)

• globalGeneratorExists → global_generator_exists
• getGlobalGenerator → get_global_generator

---

2. Backward-compatible deprecation shims

All legacy camelCase names are retained as thin wrapper aliases that:

• Emit a DeprecationWarning
• Forward directly to the new snake_case implementation

This ensures existing user code continues to work unchanged while providing a clear upgrade signal.

---

3. Ruff configuration cleanup

• Removed global suppression of N802
• Explicitly allow legacy camelCase names via [lint.pep8-naming].ignore-names
• This keeps naming exceptions explicit, intentional, and auditable

---

4. Internal cleanups (non-user-facing)

• Renamed internal helpers such as _matmul2D → _matmul2d
• Standardized internal logger construction
• Updated tests to use canonical snake_case APIs

---

Compatibility & Migration

• No breaking changes in this PR
• Users may continue using camelCase APIs short-term
• Deprecation warnings guide migration to snake_case
• Legacy names can be safely removed in a future major/minor release

---

Rationale

This change:

• Aligns Arkouda with Python ecosystem conventions (NumPy, pandas, SciPy)
• Enables stricter linting without global rule suppression
• Clarifies the long-term public API surface
• Reduces maintenance burden by eliminating naming ambiguity

Closes #5216: remove camelCase