docs(audience): drop internal pipeline name from comments

Rewrites the comments on IdentityType.ToLowercaseString, the
Identify(string) and Alias(string) overloads in ImmutableAudience,
and the matching test comments and assertion messages so they
explain why identityType is mandatory — downstream data-deletion
needs it to match a user's events — without naming the specific
internal pipeline. Same invariant, just no internal name in the
source.

The test comment on ToLowercaseString_UnknownValue_Throws is
also rewritten to read cold: leads with the rule and a concrete
bad-cast example, names what ToLowercaseString emits and how the
backend uses it, then explains why a default return would hide
the bug.

Addresses PR #696 review thread (discussion_r3122316478).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ImmutableJeffrey

src/Packages/Audience/Runtime/IdentityType.cs

@@ -17,11 +17,10 @@ public enum IdentityType
 
     internal static class IdentityTypeExtensions
     {
-        // Throws on unknown casts. The CDP pipeline requires identityType on
-        // every identify / alias event to match records to the correct
-        // identity namespace during data deletion, so an out-of-range cast
-        // must fail loudly rather than ship an event with a missing or
-        // empty namespace.
+        // Throws on unknown casts. Every identify / alias event must carry an
+        // identityType so downstream data-deletion requests can match records
+        // to the correct identity namespace; an out-of-range cast must fail
+        // loudly rather than ship an event with a missing or empty namespace.
         internal static string ToLowercaseString(this IdentityType type) => type switch
         {
             IdentityType.Passport => "passport",

src/Packages/Audience/Runtime/ImmutableAudience.cs

@@ -176,9 +176,9 @@ public static void Identify(string userId, IdentityType identityType, Dictionary
         // Attach a known user id to subsequent events. String overload for
         // providers not in IdentityType.
         //
-        // identityType is required: CDP uses it to match identify events to
-        // the correct identity namespace when processing data-deletion
-        // requests, so an event without one cannot be cleaned up.
+        // identityType is required: data-deletion processing relies on it to
+        // match identify events to the correct identity namespace, so an
+        // event without one cannot be cleaned up.
         public static void Identify(string userId, string identityType, Dictionary<string, object>? traits = null)
         {
             if (!_initialized) return;
@@ -213,9 +213,8 @@ public static void Alias(string fromId, IdentityType fromType, string toId, Iden
         // Link two user ids for the same player. String overload for
         // providers not in IdentityType.
         //
-        // fromType and toType are required: CDP uses them to match alias
-        // events to the correct identity namespaces when processing
-        // data-deletion requests.
+        // fromType and toType are required: data-deletion processing uses
+        // them to match alias events to the correct identity namespaces.
         public static void Alias(string fromId, string fromType, string toId, string toType)
         {
             if (!_initialized) return;

src/Packages/Audience/Tests/Runtime/IdentityTypeTests.cs

@@ -22,10 +22,15 @@ public void ToLowercaseString_MapsEachEnumValueToLowercaseBackendString(Identity
         [Test]
         public void ToLowercaseString_UnknownValue_Throws()
         {
-            // CDP matches identify / alias events by identityType during data
-            // deletion; an out-of-range cast would otherwise ship an event
-            // with an empty namespace that CDP cannot clean up. Fail loud so
-            // the programmer error surfaces at the call site instead.
+            // An out-of-range cast like `(IdentityType)999` must throw.
+            // ToLowercaseString emits the "identityType" string on every
+            // identify / alias event (e.g. "passport"), and the backend uses
+            // that string to find and delete a user's events on request.
+            //
+            // An unknown enum value must throw so the bug surfaces at the
+            // cast site. Returning a default string instead would ship the
+            // event with a blank identityType — invisible to the deletion
+            // lookup — and hide the bug.
             var invalid = (IdentityType)999;
 
             Assert.Throws<ArgumentOutOfRangeException>(() => invalid.ToLowercaseString());

src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs

@@ -142,7 +142,7 @@ public void Identify_InvalidIdentityTypeCast_Throws()
             Assert.Throws<ArgumentOutOfRangeException>(
                 () => ImmutableAudience.Identify("user1", invalid),
                 "invalid enum cast must throw so a broken call fails loud rather than " +
-                "shipping an identify event CDP cannot match for deletion");
+                "shipping an identify event that cannot be matched for deletion");
         }
 
         [Test]
@@ -155,7 +155,7 @@ public void Alias_InvalidIdentityTypeCast_Throws()
             Assert.Throws<ArgumentOutOfRangeException>(
                 () => ImmutableAudience.Alias("fromId", invalid, "toId", IdentityType.Steam),
                 "invalid enum cast must throw so a broken alias call fails loud rather " +
-                "than shipping an event CDP cannot match for deletion");
+                "than shipping an event that cannot be matched for deletion");
         }
 
         [Test]