Why: I2 increments 1-2 shipped the agent-intent ports (SemanticScorer,
CommandGenerator); the backend still had no implementation, so the slow
lane could not be enabled in the product.
Evidence: go test ./... green; lint-boundaries ok; the two new
runtime.intentSemantic / runtime.intentGenerator flags are registered
with default false and the gate defaults to the I1 recognizer when both
are off (TestIntentSlowLaneFlagsDefaultOff, TestGate*).
Impact: no behavior change by default; enabling runtime.intentSemantic
routes ambiguous rule matches through embedding cosine scoring, and
runtime.intentGenerator lets the lightweight model propose commands on
fallback with library-side fail-closed validation. Nested agent-intent
pin moves to 343b1e6 (I2 increments 1-2).
Refs: I2 increment 3
