router: add ActionResolutionMethod type and ResolvedBy field to Slots

Five disjoint values tracking which component selected the exact function:
grammar_fixed, grammar_matcher, extractor_raw, extractor_llm_text,
fallback_matcher. Slots.ResolvedBy carries provenance at the selection
point.

internal/dialogue/session.go

@@ -31,6 +31,10 @@ type Slots struct {
 	Fn      string
 	Args    []string
 	HasFn   bool
+	// ResolvedBy — which component selected the exact function. Mirrors
+	// router.Slots.ResolvedBy. Carried as a string because dialogue cannot
+	// import router (import cycle).
+	ResolvedBy string
 }
 
 // Turn represents one utterance in a multi-turn dialogue history.

internal/router/intent.go

@@ -74,6 +74,34 @@ const (
 	IntentSystem   Intent = "system"
 )
 
+// ActionResolutionMethod — which component actually selected the exact
+// function. Recorded for observability so a trace can name the selection
+// mechanism without re-deriving it from the route producer and surrounding
+// claims. Five disjoint values; empty means no function was resolved.
+type ActionResolutionMethod string
+
+const (
+	// ActionResolutionGrammarFixed — a stage-0 grammar hardcodes a fixed
+	// canonical fn (praxis lifecycle, task-status). No matcher involved.
+	ActionResolutionGrammarFixed ActionResolutionMethod = "grammar_fixed"
+
+	// ActionResolutionGrammarMatcher — a stage-0 grammar invokes the
+	// ActMatcher to select fn (wakeword-act fast path).
+	ActionResolutionGrammarMatcher ActionResolutionMethod = "grammar_matcher"
+
+	// ActionResolutionExtractorRaw — post-route Extractor.Acts.Match over
+	// the original/raw routed utterance.
+	ActionResolutionExtractorRaw ActionResolutionMethod = "extractor_raw"
+
+	// ActionResolutionExtractorLLMText — the LLM produced cleaned
+	// Slots.Text, then Extractor.Acts.Match selected fn from it.
+	ActionResolutionExtractorLLMText ActionResolutionMethod = "extractor_llm_text"
+
+	// ActionResolutionFallbackMatcher — ResolveActionCandidate ran the
+	// fallback matcher because routing/extraction left HasFn=false.
+	ActionResolutionFallbackMatcher ActionResolutionMethod = "fallback_matcher"
+)
+
 // Slots — per-intent extracted arguments (stage 2). Not every field is set for
 // every intent; the Intent decides which matter. A slot that doesn't parse
 // leaves its Has* flag false — the daemon's SLM last-resort lane picks it up
@@ -93,6 +121,11 @@ type Slots struct {
 	Args  []string
 	HasFn bool
 
+	// ResolvedBy — which component actually selected the exact function.
+	// Set when Fn is set; empty when HasFn is false. Travels with the slot
+	// so provenance is known at the selection point, not reconstructed later.
+	ResolvedBy ActionResolutionMethod
+
 	// Fact: structured (key,value) the loop will evaluate predicates against.
 	// "drank water" → key=water; "slept 6h" → key=sleep, value=6h. The value
 	// is the raw string the daemon json-encodes before WriteFact.