Preserve Decimal values as numeric literals in client-side binding

[Shubham-Padkonde]

1. Issue: Fixes SNOW-2248950: converter.py: parameter binding for decimal.Decimal produces incorrect SQL #2455.

2. Pre-review checklist:

• New automated tests
• New logging messages
• New telemetry messages
• Authorization changes
• New credentials
• OCSP changes
• New dependency

3. Finite Decimal parameters were converted to strings and then quoted, so Decimal('1.3') produced a string literal. Preserve finite Decimal values until quoting and use their exact decimal representation, without converting through float. Keep non-finite values quoted and server-side binding unchanged. Includes mixed-list, precision, scale, negative-zero and special-value tests plus release notes.

Validation: six regression cases fail before the fix; all 38 converter tests pass afterward. Black, isort and flake8 checks passed. No live Snowflake integration tests were run.

Prepared with Codex assistance.

[Shubham-Padkonde]

Merged current main and resolved the release-note conflict by keeping the Decimal binding fix under the current unreleased section alongside the upstream entries. All 38 converter tests pass on Windows/Python 3.13 (pytest test/unit/test_converter.py --noconftest); this isolated converter run omits the integration fixtures and reports three missing-plugin configuration warnings. No live Snowflake tests were run. git diff --check passes. Prepared with Codex assistance.