Add dotnet format pre-commit enforcement and fix 70 SonarCloud formatting violations

[Copilot]

Implements mandatory dotnet format pre-commit hook and remediates all existing whitespace formatting violations across the codebase.

Changes

Pre-Commit Hook Infrastructure

• scripts/pre-commit - Bash hook that runs dotnet format on staged C# files, re-stages formatted output
• scripts/install-git-hooks.{sh,ps1} - Cross-platform installers with single-command setup
• Formats only changed files; handles multiple solutions; provides colored output

Development Standards

• TODO/DEVELOPMENT_RULES.md - 15 mandatory rules with Rule Bump the major group with 9 updates #1: Always run dotnet format before committing
• Updated CONTRIBUTING.md to promote automated hook installation
• Added scripts/README.md and docs/pre-commit-hook-testing.md for maintainability

Formatting Fixes

• Fixed 70 files with whitespace violations (1,676+/1,152- lines)
• FlinkDotNet: 48 files, LocalTesting: 19 files, NativeFlinkDotnetTesting: 3 files
• All solutions now pass dotnet format --verify-no-changes

Installation

# Linux/macOS
./scripts/install-git-hooks.sh

# Windows
.\scripts\install-git-hooks.ps1

Pre-Commit Behavior

$ git commit -m "feat: add feature"
Running pre-commit checks...
Formatting changed C# files...
✓ Formatted: FlinkDotNet/FlinkDotNet.sln
  ↳ Restaging: FlinkDotNet/Some/File.cs
✓ Pre-commit checks passed!

Bypass (emergency use only): git commit --no-verify

Original prompt

Continue implement root/TODO. Add another rule to TODO that always run dotnet format before commit changes.

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