feat(cel-proto-parser): add CEL proto parser and deparser package

- Add new cel-proto-parser package for working with CEL ASTs
- Implement CelProtoParser class to parse CEL proto files and generate TypeScript types
- Implement deparser to convert CEL AST back to expression strings
- Support all CEL expression types: constants, identifiers, field access, function calls, operators, ternary, lists, maps, message construction, comprehensions
- Add AST helper generation for constructing CEL AST nodes
- Include comprehensive test suite with 34 passing tests
- Include CEL syntax.proto fixture from official cel-spec

Author: pyramation

packages/cel-proto-parser/README.md

@@ -0,0 +1,98 @@
+# cel-proto-parser
+
+CEL (Common Expression Language) proto parser and deparser for TypeScript.
+
+## Overview
+
+This package provides tools for working with CEL (Common Expression Language) Abstract Syntax Trees (ASTs):
+
+1. **Proto Parser**: Parse CEL protobuf definitions to generate TypeScript types
+2. **Deparser**: Convert CEL AST back to CEL expression strings
+3. **AST Helpers**: Factory functions for constructing CEL AST nodes
+
+## Installation
+
+```bash
+npm install cel-proto-parser
+```
+
+## Usage
+
+### Deparser
+
+Convert CEL AST to expression strings:
+
+```typescript
+import { deparse, Expr } from 'cel-proto-parser';
+
+// Simple expression: x > 5
+const expr: Expr = {
+  callExpr: {
+    function: '_>_',
+    args: [
+      { identExpr: { name: 'x' } },
+      { constExpr: { int64Value: 5 } }
+    ]
+  }
+};
+
+console.log(deparse(expr)); // Output: "x > 5"
+```
+
+### Proto Parser
+
+Generate TypeScript types from CEL proto files:
+
+```typescript
+import { CelProtoParser } from 'cel-proto-parser';
+
+const parser = new CelProtoParser('path/to/syntax.proto', {
+  outDir: './generated',
+  types: { enabled: true },
+  enums: { enabled: true },
+  utils: { astHelpers: { enabled: true } },
+  deparser: { enabled: true }
+});
+
+parser.write();
+```
+
+## CEL Expression Types
+
+The deparser supports all CEL expression types:
+
+- **Constants**: `null`, `true`, `false`, integers, floats, strings, bytes
+- **Identifiers**: `request`, `user`, etc.
+- **Field Access**: `request.auth.claims`
+- **Function Calls**: `size(list)`, `str.startsWith("prefix")`
+- **Operators**: `+`, `-`, `*`, `/`, `%`, `==`, `!=`, `<`, `<=`, `>`, `>=`, `&&`, `||`, `!`, `-` (unary)
+- **Ternary**: `condition ? trueExpr : falseExpr`
+- **Index Access**: `list[0]`, `map["key"]`
+- **Lists**: `[1, 2, 3]`
+- **Maps**: `{"key": value}`
+- **Message Construction**: `MyMessage{field: value}`
+- **Macros**: `has()`, `all()`, `exists()`, etc.
+
+## API Reference
+
+### `deparse(expr: Expr, options?: DeparserOptions): string`
+
+Converts a CEL AST expression to a string.
+
+Options:
+- `spaces`: Whether to add spaces around operators (default: `true`)
+
+### `CelProtoParser`
+
+Parses CEL proto files and generates TypeScript code.
+
+Constructor options:
+- `outDir`: Output directory for generated files
+- `types.enabled`: Generate TypeScript interfaces
+- `enums.enabled`: Generate TypeScript enums
+- `utils.astHelpers.enabled`: Generate AST helper functions
+- `deparser.enabled`: Generate deparser module
+
+## License
+
+MIT