Interpolation safety check: bypassed by one explicit t(), no else on the mode switch, mode name mismatch

[zantvoort]

The runtime backstop for templates built without the compiler plugin has three gaps (storm-kotlin/src/main/kotlin/st/orm/template/TemplateString.kt):

1. The check at :142 fires only when !autoInterpolation && !interpolateCalled. One explicit t() call sets interpolateCalled, after which every other raw interpolation in the same template passes silently: { "SELECT ${t(User::class)} FROM user WHERE name = '$name'" } concatenates $name into the SQL with no warning at any log level. Counting interpolations against t() calls would close this.
2. The when over the mode at :152-156 has no else, so a typo'd property value silently disables the check entirely. Unknown values should fail fast.
3. The code names the disabled mode off; docs/configuration.md names it none. Align them.

Also worth deciding: the default mode is warn, which means a missing compiler plugin turns injection into a log line. A throw default is the safer contract; if that is too breaking for this milestone, the docs should at least tell production users to set throw.