feat: Add prompt support (#351)

* feat: add prompt support with typed argument handling

- Implement #[prompt], #[prompt_router], and #[prompt_handler] macros
- Add automatic JSON schema generation from Rust types for arguments
- Support flexible async handler signatures with automatic adaptation
- Create PromptRouter for efficient prompt dispatch
- Include comprehensive tests and example implementation

This enables MCP servers to provide reusable prompt templates that
LLMs can discover and invoke with strongly-typed parameters, similar
to the existing tool system but optimized for prompt use cases.

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: unify parameter handling between tools and prompts

- Replace Arguments<T> with Parameters<T> for consistent API
- Create shared common module for tool/prompt utilities
- Modernize async handling with futures::future::BoxFuture
- Move cached_schema_for_type to common module for reuse
- Update error types from rmcp::Error to rmcp::ErrorData
- Add comprehensive trait implementations for parameter extraction

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: extract Parameters wrapper to shared module and unify trait usage

- Move Parameters type from common.rs to dedicated wrapper/parameters.rs module
- Unify extractor traits by using FromContextPart for both tools and prompts
- Remove duplicate FromToolCallContextPart and FromPromptContextPart traits
- Add structured output support to Json wrapper with IntoCallToolResult impl
- Improve error messages with more descriptive panic for schema serialization
- Update all imports across codebase to use new module path
- Clean up trailing whitespace and formatting inconsistencies

This consolidates parameter extraction logic and reduces code duplication
between tool and prompt handlers while maintaining backward compatibility.

* chore: remove committed .egg-info directory and update gitignore

* docs: fix documentation formatting

.gitignore

@@ -13,9 +13,16 @@ Cargo.lock
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
 .vscode/
+
+# Python artifacts (for test directories)
+*.egg-info/
+__pycache__/
+*.pyc
+*.pyo
+
 # RustRover
 #  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
+#.idea/