One structural rule (secrets.RedactEndpoint / CredentialKey / RedactArgs)
replaces mcpsetup.RedactURL's query-only masking. Userinfo and fragments are
dropped or masked, query and fragment keys are decoded before classification,
unparseable endpoints render as <redacted>, and transport diagnostics keep
error identity while omitting peer-supplied prose.
Operational values (install, approval fingerprints, persistence) are untouched;
preview and plan responses add separate display fields that the desktop mirror
and confirmation UI render.
Rebased onto the launcher-aware NameFromArgv: names derive from the original
argv but never from a value the display projection masked, so build-flag values
such as `go run -exec` still resolve. Install classification reads the typed
HTTP status instead of sniffing the server name out of the message.
Fixes#11785
