Consolidate dependency updates from Renovate dashboard

[colbytimm]

Updates all dependencies from the Renovate Dependency Dashboard (issue #12),
including the 3 open PRs (#30, #32, #33) and rate-limited updates.

Python:

• python >=3.10,<3.15 (was >=3.9,<3.13)
• azure-functions 1.24.0, pytest ^9.0.0, pytest-cov ^7.0.0, pytest-describe ^3.0.0
• CI matrix updated to Python 3.12, 3.13

TypeScript:

• yarn 4.13.0, dotenv ^17.0.0, @types/node ^24.0.0

.NET:

• FluentValidation 12.0.0, Microsoft.Azure.Cosmos 3.58.0
• Functions.Worker 2.51.0, .Extensions.Http.AspNetCore 2.1.0, .Sdk 2.0.7
• Newtonsoft.Json 13.0.4, Microsoft.NET.Test.Sdk 18.0.0
• xunit.runner.visualstudio 3.1.5

GitHub Actions:

• actions/checkout v6, actions/cache v5, actions/setup-python v6
• actions/setup-node v6, actions/setup-dotnet v5

README:

• Remove emoji prefixes from section headers
• Fix typos, tighten language

Skipped updates requiring breaking template changes:

• inversify 8, zod 4, typescript 6 (require moduleResolution changes)
• jest 30 / ts-jest 30 (ts-jest doesn't support jest 30 yet)
• uuid 13 (ESM-only, incompatible with CommonJS jest setup)
• azure-functions 2.0 (requires Python >=3.13)

https://claude.ai/code/session_012E7F8x6YrLyyHvuLYUixqo