feat: WASM bindings for cedar-policy-mcp-schema-generator (cedar-policy#64)

Add `cedar-policy-mcp-schema-generator-wasm`, a thin wasm-bindgen
wrapper around the existing Rust SchemaGenerator. Enables JavaScript
and TypeScript environments (Node.js, browsers) to generate Cedar
schemas from MCP tool descriptions with identical behavior to the
Rust implementation.

Motivated by @lianah's recommendation in cedar-policy#63 to use WASM bindings
instead of a TypeScript reimplementation.

Changes to cedar-policy-mcp-schema-generator:
- Add SchemaGenerator::from_cedarschema_str() and
  from_cedarschema_str_with_config() convenience constructors
- Add SchemaGenerator::get_schema_as_str() for human-readable output
- Add SchemaParseError variant to SchemaGeneratorError
- 6 new unit tests for the above APIs

WASM bindings crate:
- Single generateSchema() function exposed via wasm-bindgen
- All SchemaGeneratorConfig options exposed (camelCase JS naming)
- Returns JSON with schema, schemaJson, error, and isOk fields
- Zero direct dependency on cedar-policy-core (all parsing
  delegated to generator crate's from_cedarschema_str)
- 3 Rust unit tests
- 8 wasm-bindgen-test integration tests (basic generation,
  multi-tool, config options, error handling, config defaults)

Signed-off-by: tommylauren <tfarley@utexas.edu>
Co-authored-by: tommylauren <tfarley@utexas.edu>

Author: tomjwxf

rust/Cargo.lock

@@ -1,6 +1,7 @@
 [workspace]
 members = [
 	"cedar-policy-mcp-schema-generator",
+	"cedar-policy-mcp-schema-generator-wasm",
 	"mcp-tools-sdk",
 ]
 

rust/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "cedar-policy-mcp-schema-generator-wasm"
+description = "WASM bindings for cedar-policy-mcp-schema-generator, exposing SchemaGenerator to JavaScript/TypeScript."
+version = "0.1.0"
+
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+categories.workspace = true
+keywords.workspace = true
+homepage.workspace = true
+repository.workspace = true
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+cedar-policy-mcp-schema-generator = { path = "../cedar-policy-mcp-schema-generator" }
+mcp-tools-sdk = { path = "../mcp-tools-sdk" }
+wasm-bindgen = "0.2"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+
+[dev-dependencies]
+wasm-bindgen-test = "0.3"
+serde_json = "1.0"
+
+[lints]
+workspace = true

rust/cedar-policy-mcp-schema-generator-wasm/Cargo.toml

@@ -0,0 +1,109 @@
+# cedar-policy-mcp-schema-generator-wasm
+
+WASM bindings for [cedar-policy-mcp-schema-generator](../cedar-policy-mcp-schema-generator/), exposing `SchemaGenerator` to JavaScript and TypeScript via `wasm-bindgen`.
+
+This enables Node.js and browser environments to generate Cedar authorization schemas from MCP tool descriptions with the **exact same behavior** as the Rust implementation, including correct handling of:
+
+- JSON `number` as `Long` or `Decimal` (configurable)
+- `additionalProperties` as Cedar tagged entities
+- Namespaced type deduplication for nested objects
+
+## Usage
+
+```javascript
+const { generateSchema } = require('@cedar-policy/mcp-schema-generator-wasm');
+
+const stub = `
+namespace MyServer {
+    @mcp_principal
+    entity User;
+    @mcp_resource
+    entity McpServer;
+    action "call_tool" appliesTo {
+        principal: [User],
+        resource: [McpServer]
+    };
+}
+`;
+
+const tools = JSON.stringify([
+  {
+    name: 'read_file',
+    description: 'Read a file from disk',
+    inputSchema: {
+      type: 'object',
+      properties: { path: { type: 'string' } },
+      required: ['path'],
+    },
+  },
+]);
+
+const result = JSON.parse(generateSchema(stub, tools));
+
+if (result.isOk) {
+  console.log(result.schema);     // Human-readable .cedarschema
+  console.log(result.schemaJson); // JSON for Cedar WASM isAuthorized()
+} else {
+  console.error(result.error);
+}
+```
+
+## API
+
+### `generateSchema(schemaStub, toolsJson, configJson?)`
+
+| Parameter | Type | Description |
+|-----------|------|-------------|
+| `schemaStub` | `string` | Cedar schema stub with `@mcp_principal` and `@mcp_resource` annotations |
+| `toolsJson` | `string` | MCP tool descriptions as JSON (the `tools` array from `tools/list`) |
+| `configJson` | `string?` | Optional configuration as JSON |
+
+**Returns:** JSON string with fields:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `schema` | `string \| null` | Generated Cedar schema as `.cedarschema` text |
+| `schemaJson` | `string \| null` | Generated schema as JSON (for `isAuthorized()`) |
+| `error` | `string \| null` | Error message if generation failed |
+| `isOk` | `boolean` | Whether generation succeeded |
+
+### Configuration
+
+```json
+{
+  "includeOutputs": false,
+  "objectsAsRecords": false,
+  "eraseAnnotations": true,
+  "flattenNamespaces": false,
+  "numbersAsDecimal": false
+}
+```
+
+| Option | Default | Description |
+|--------|---------|-------------|
+| `includeOutputs` | `false` | Include tool output schemas in actions |
+| `objectsAsRecords` | `false` | Use records instead of entities for objects without `additionalProperties` |
+| `eraseAnnotations` | `true` | Remove `@mcp_*` annotations from output |
+| `flattenNamespaces` | `false` | Flatten all types into a single namespace |
+| `numbersAsDecimal` | `false` | Encode JSON `number` as Cedar `Decimal` instead of `Long` |
+
+## Building
+
+```bash
+# Install wasm-pack
+cargo install wasm-pack
+
+# Build for Node.js
+wasm-pack build --target nodejs --scope cedar-policy
+
+# Build for browsers
+wasm-pack build --target web --scope cedar-policy
+```
+
+## Relationship to the Rust Generator
+
+This crate is a thin `wasm-bindgen` wrapper around the existing `cedar-policy-mcp-schema-generator` Rust crate. All schema generation logic, type mapping, and edge case handling is delegated to the Rust implementation. The WASM bindings add no independent logic.
+
+## License
+
+Apache-2.0