feat: add uv lockfile, frozen nox installs, and uv documentation

[BradyPlanden]

Add uv.lock for reproducible dependency resolution and update the tooling and documentation to support uv as a first-class workflow alongside pip.

• Add uv.lock
• Add uv lock --check CI step to ensure lockfile stays in sync
• Add uv package ecosystem to dependabot for automated lockfile updates
• Replace nox session.install() with uv sync --frozen via install_locked() helper for deterministic CI environments
• Simplify nox -s dev session to use uv sync --frozen
• Remove no-op strategy: fail-fast: false from memory single-matrix CI job
• Exclude uv.lock from pre-commit large file check
• Update install-from-source docs with uv as recommended dev workflow
• Add uv/pip tabs to user install docs (Linux, macOS, Windows)
• Update CONTRIBUTING.md with uv alternatives for pre-commit and testing

Fixes # (issue)

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #)

Important checks:

Please confirm the following before marking the PR as ready for review:

• No style issues: nox -s pre-commit
• All tests pass: nox -s tests
• The documentation builds: nox -s doctests
• Code is commented for hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.29%. Comparing base (4f78ef0) to head (82a255b).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5460   +/-   ##
=======================================
  Coverage   98.29%   98.29%           
=======================================
  Files         337      337           
  Lines       30958    30950    -8     
=======================================
- Hits        30429    30423    -6     
+ Misses        529      527    -2     

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