The 'Always Allow' button is now driven entirely by the server-supplied
allowed_decisions palette. The card no longer peeks at
context.mcp_connector_id to decide whether to render the button, and no
longer fires a separate trust-tool HTTP call on click - one
{type: 'approve_always'} dispatch is enough; the agent middleware
handles the in-memory promotion and (for MCP tools) the database save
via its trusted_tool_saver callback.
Drops the dead trustMCPTool / untrustMCPTool service helpers - they had
no remaining callers after this rework. The backing HTTP routes are
kept on the server as a programmatic surface.
