Update dependency specification to version ranges for Renovate compatibility

[harryswift01]

Summary

This PR updates the dependency declarations in pyproject.toml from strict pinned versions (==x.y.z) to version ranges.
The goal is to enable Renovate to manage Python dependencies effectively, allowing automated upgrades while ensuring that only compatible ranges are kept (via rangeStrategy: replace).

Changes

Convert pinned dependencies to version ranges

• Updated all project.dependencies from ==x.y.z to ranges of the form:
  • >=<current_version>,<next_major_version>
• Updated project.optional-dependencies (testing, pre-commit, docs) in the same way.
• Ranges were selected to:
  • Keep the project on the current major version
  • Allow Renovate to propose upgrades when out-of-range
  • Prevent untested or breaking major versions from being used automatically.

Impact

• Allows Renovate to automatically manage and update Python dependencies
• Ensures CI verifies updates before ranges change
• Prevents drift to incompatible versions
• Makes dependency maintenance easier and safer long-term