Convert mounted servers to MountedProvider (#2635)

* Simplify Provider interface and consolidate docket registration

- Remove get_http_routes from Provider (unused)
- Remove ProviderLifespanConfig, _base_lifespan, _register_tasks
- Remove supports_tasks flag from Provider.__init__
- Consolidate all docket registration in server._docket_lifespan()
- Simplify lifespan() to take no parameters
- Move MountedProvider to separate module

* Fix control flow in ComponentService resource methods

* Move providers to server/providers

* Ensure MountedProvider get_* methods go through middleware

* Fix get_resource to only return concrete resources

Reverts template-checking in get_resource that broke task execution.
Tasks need access to the original template, not instantiated resources.

* Move prefix utilities into mounted.py, deprecate import_server

- Add resource prefix functions (add/remove/has_resource_prefix) to mounted.py
- Deprecate import_server with warning to use mount() instead
- Add tool_names uniqueness validation in MountedProvider

* Fix provider iteration order and remove dead _is_mounted flag

- Remove unused _is_mounted flag (MountedProvider.lifespan() calls _lifespan
  not _lifespan_manager, so the flag was never checked)
- Fix provider iteration: change reversed() to forward order in execution
  methods (_call_tool, _read_resource_middleware, _get_prompt_content_middleware)
  to match documented "first non-None wins" semantics
- Fix ComponentService to handle prefix-less mounted servers using
  _strip_tool_prefix()/_strip_resource_prefix() methods
- Update conflict resolution tests to expect first-registered provider wins
- Add regression tests for Docket behavior and prefix-less ComponentService

* Add TaskComponents type and exception handling for provider task registration

- Create TaskComponents dataclass with FunctionTool/FunctionResource/etc. types
  for proper typing of get_tasks() return value
- Add try/except wrapper around provider.get_tasks() in _docket_lifespan for
  consistent error handling (warn + continue or raise based on settings)
- Remove type: ignore comments from server.py task registration loop

examples/providers/sqlite/server.py

@@ -20,8 +20,9 @@ from typing import Any
 import aiosqlite
 from rich import print
 
-from fastmcp import Client, FastMCP, Provider
+from fastmcp import Client, FastMCP
 from fastmcp.server.context import Context
+from fastmcp.server.providers import Provider
 from fastmcp.tools.tool import Tool, ToolResult
 
 DB_PATH = Path(__file__).parent / "tools.db"