feat(promptly): add lsp, fmt, and check implementations

[yesudeep]

feat(promptly): add lsp, fmt, and check implementations

Add the promptly CLI tool with LSP server, formatter, and linter
capabilities for .prompt files.

Core features:

• LSP server with diagnostics, hover, and completion support
• Formatter for consistent .prompt file formatting
• Linter with YAML validation and Handlebars syntax checking
• Shell completions generation (bash, zsh, fish, powershell)

Parser improvements:

• Support license headers and shebangs before frontmatter
• Allow blank lines mixed with comments before ---
• Updated regex in all 5 runtimes (Rust, Python, Java, JS, Go)
• Added tests for new frontmatter parsing behavior

CI/CD improvements:

• Add format checks to Java, Go, and JS workflows
• Rename test.yml to js.yml for consistency
• Tests now depend on format checks passing

Editor support:

• JetBrains plugin with syntax highlighting and LSP integration
• Enhanced VS Code extension with LSP client and snippets
• Updated Emacs and Vim plugins
• Tree-sitter grammar for .prompt files

New packages:

• rs/promptly - Rust CLI implementation
• packages/promptly - npm wrapper for cross-platform distribution
• packages/jetbrains - IntelliJ/WebStorm plugin
• packages/treesitter - Tree-sitter grammar