fix(mcp): restore overwrite param schema for external MCP clients (#818)

AliasChoices on `overwrite: bool | None` in write_note caused FastMCP to
generate a broken JSON schema where external clients (e.g. Claude Code)
saw the parameter as type null-only. The boolean value was silently
dropped, so `overwrite=True` arrived as None at the function body.

Revert overwrite to a plain `bool | None = None` parameter. FastMCP now
generates the correct `anyOf: [boolean, null]` schema, and external
clients can send `overwrite=true` as intended.

The `directory` alias (folder/dir/path) is unaffected — AliasChoices on
a required `str` parameter does not exhibit this schema generation issue.

Add regression test: test_write_note_overwrite_canonical_via_mcp verifies
that overwrite=True reaches the function body through the MCP protocol.

Co-authored-by: Paul Hernandez <phernandez@users.noreply.github.com>
Signed-off-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>

src/basic_memory/mcp/tools/write_note.py

@@ -35,11 +35,10 @@ async def write_note(
     tags: list[str] | str | None = None,
     note_type: str = "note",
     metadata: Annotated[dict | None, BeforeValidator(coerce_dict)] = None,
-    # Force/replace are the file-write idioms models default to.
-    overwrite: Annotated[
-        bool | None,
-        Field(default=None, validation_alias=AliasChoices("overwrite", "force", "replace")),
-    ] = None,
+    # Simple bool so FastMCP generates a correct boolean schema for external clients.
+    # AliasChoices caused external clients (e.g. Claude Code) to receive a broken schema
+    # where overwrite appeared as type null-only, silently dropping the value (issue #818).
+    overwrite: bool | None = None,
     output_format: Literal["text", "json"] = "text",
     context: Context | None = None,
 ) -> str | dict: