feat(mcp): assemble the 8-tool toolkit with capability gating, proven via real dispatch

Also fixes async-test DB isolation: test_mcp_toolkit.py drives real MCP
dispatch, which runs tool functions' ORM calls on a sync_to_async worker
thread outside pytest-django's per-test atomic transaction, so writes
committed there weren't rolled back and leaked into later tests. Sets
DJANGO_ALLOW_ASYNC_UNSAFE for the async ORM setup calls and flushes the
Printer table after this file's tests via conftest.py.

bambu_run/mcp/toolkit.py

@@ -0,0 +1,28 @@
+"""Assembles the 8-tool bambu_run MCP toolkit, capability-tagged per the spec."""
+from __future__ import annotations
+
+from mcp_gate import Toolkit
+
+from bambu_run.mcp.filaments import get_filament, list_filaments
+from bambu_run.mcp.jobs import get_print_job, get_print_statistics, list_print_jobs
+from bambu_run.mcp.status import get_hardware_health, get_metrics_history, get_printer_status
+
+
+def build_toolkit() -> Toolkit:
+    """Build the bambu_run MCP toolkit: 8 tools across read_printer,
+    read_print_history, and read_filament.
+
+    Called fresh by each entry point rather than shared as a module-level
+    singleton, so tests (and multiple concurrent Gates, if ever needed) get
+    an isolated Toolkit instance rather than sharing registration state.
+    """
+    kit = Toolkit("bambu_run")
+    kit.tool(requires="read_printer")(get_printer_status)
+    kit.tool(requires="read_printer")(get_metrics_history)
+    kit.tool(requires="read_printer")(get_hardware_health)
+    kit.tool(requires="read_print_history")(list_print_jobs)
+    kit.tool(requires="read_print_history")(get_print_job)
+    kit.tool(requires="read_print_history")(get_print_statistics)
+    kit.tool(requires="read_filament")(list_filaments)
+    kit.tool(requires="read_filament")(get_filament)
+    return kit