Only a successful snapshot settled a native todo block. A `read_todos`
narrowed by a filter and a server `UpdateTodosError` both went
unanswered: no `tool_execution_end`, so the card animated forever, and
no `toolResult`, so `buildSessionContext` stripped the block on rebuild.
Every completed native todo call now settles. The refusal path carries
no `details.phases` -- `event-controller` feeds that straight into
`setTodos`, so echoing the current list back would let a call that
changed nothing overwrite live panel state. A server error is carried
through as a failed result instead of collapsing into the benign no-op.
Each regression is covered by a test verified to fail without its fix.
Diogo Soares Rodrigues
0639246d27