Clean up the PromptKit upgrade

internal/core/artifacts/artifacts.go

@@ -1,6 +1,7 @@
 package artifacts
 
 import (
+	"strings"
 	"time"
 )
 
@@ -33,6 +34,27 @@ type LLMProfileManifest struct {
 	ReasoningEffort string `json:"reasoning_effort,omitempty"`
 }
 
+// Normalized returns the canonical representation used for manifest identity
+// and publication.
+func (profile LLMProfileManifest) Normalized() LLMProfileManifest {
+	profile.ID = strings.TrimSpace(profile.ID)
+	profile.Provider = strings.TrimSpace(profile.Provider)
+	profile.Model = strings.TrimSpace(profile.Model)
+	profile.BackendID = strings.TrimSpace(profile.BackendID)
+	profile.ReasoningEffort = strings.TrimSpace(profile.ReasoningEffort)
+	return profile
+}
+
+// IdentityKey returns an opaque, deterministic key for the effective profile.
+func (profile LLMProfileManifest) IdentityKey() string {
+	profile = profile.Normalized()
+	return profile.ID + "\x00" +
+		profile.Provider + "\x00" +
+		profile.Model + "\x00" +
+		profile.BackendID + "\x00" +
+		profile.ReasoningEffort
+}
+
 type ReferenceProvenance struct {
 	Stage            string `json:"stage,omitempty"`
 	StepID           string `json:"step_id,omitempty"`