fix(cli): defer FastAPI and app imports out of CLI startup

Every basic-memory CLI invocation paid roughly 2 seconds of module-import
cost before any work started, which blew the Claude Code plugin's
SessionStart hook budget on cold machines (#886). The cost came from
module-level imports that pulled the entire server stack into CLI startup:

- mcp/async_client.py imported FastAPI at module level, so every consumer
  of get_client() loaded FastAPI even for cloud-routed or help-only paths.
- mcp/clients/*.py imported call_* helpers from basic_memory.mcp.tools.utils,
  which executes the whole tools package __init__ — every MCP tool module
  plus fastmcp and the mcp SDK.
- mcp/project_context.py imported fastmcp.Context and ToolError eagerly.
- CLI command modules (tool, ci, schema) imported MCP tool functions at
  module level; db and the import_* commands pulled SQLAlchemy/Alembic and
  the markdown/file-service stack; status/doctor/orphans/command_utils
  imported ToolError (the mcp SDK) and basic_memory.db.
- schemas/base.py imported dateparser (~0.13s) for one helper function.

The fix only defers imports to the point of use (no behavior changes):
FastAPI now loads inside _resolve_local_asgi_database alongside the
existing lazy api.app import, so it is only paid when a request actually
routes through the in-process ASGI transport; the typed clients import
call_* per method; project_context uses PEP 563 annotations with Context
under TYPE_CHECKING; the CLI command modules import their heavy
dependencies inside the command bodies. Tests that patched the old
module-level aliases now patch the source modules instead.

Measured on a warm cache (python -X importtime / wall time):
- import basic_memory.cli.main: 1.92s -> 0.45s
- bm --help: 2.40s -> 0.52s
- bm tool search-notes --help: 2.40s -> 0.86s

A regression test asserts that importing the CLI entry module with full
command registration leaves fastapi, sqlalchemy, alembic, fastmcp, mcp,
basic_memory.api.app, basic_memory.db, basic_memory.markdown,
basic_memory.mcp.tools, and basic_memory.services out of sys.modules.

Fixes #886

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: phernandez <paul@basicmachines.co>

src/basic_memory/cli/commands/schema.py

@@ -20,9 +20,10 @@ from basic_memory.cli.app import app
 from basic_memory.cli.commands.command_utils import run_with_cleanup
 from basic_memory.cli.commands.routing import force_routing, validate_routing_flags
 from basic_memory.config import ConfigManager
-from basic_memory.mcp.tools import schema_diff as mcp_schema_diff
-from basic_memory.mcp.tools import schema_infer as mcp_schema_infer
-from basic_memory.mcp.tools import schema_validate as mcp_schema_validate
+
+# MCP tool functions are imported inside each command: importing
+# basic_memory.mcp.tools loads the entire tool stack (fastmcp, mcp SDK,
+# SQLAlchemy), which would slow every CLI invocation, including --help (#886).
 
 console = Console()
 
@@ -189,6 +190,9 @@ def validate(
     Use --local to force local routing when cloud mode is enabled.
     Use --cloud to force cloud routing when cloud mode is disabled.
     """
+    # Deferred: loading the MCP tool stack at module import slows CLI startup (#886).
+    from basic_memory.mcp.tools import schema_validate as mcp_schema_validate
+
     try:
         validate_routing_flags(local, cloud)
         project_name = _resolve_project_name(project)
@@ -272,6 +276,9 @@ def infer(
     Use --local to force local routing when cloud mode is enabled.
     Use --cloud to force cloud routing when cloud mode is disabled.
     """
+    # Deferred: loading the MCP tool stack at module import slows CLI startup (#886).
+    from basic_memory.mcp.tools import schema_infer as mcp_schema_infer
+
     try:
         validate_routing_flags(local, cloud)
         project_name = _resolve_project_name(project)
@@ -352,6 +359,9 @@ def diff(
     Use --local to force local routing when cloud mode is enabled.
     Use --cloud to force cloud routing when cloud mode is disabled.
     """
+    # Deferred: loading the MCP tool stack at module import slows CLI startup (#886).
+    from basic_memory.mcp.tools import schema_diff as mcp_schema_diff
+
     try:
         validate_routing_flags(local, cloud)
         project_name = _resolve_project_name(project)