fix(copilot): restrict model normalization to claude-prefixed names

GPT model IDs use dots in the pricing catalog (e.g. gpt-5.4) so
applying strings.ReplaceAll universally would convert gpt-5.4 to
gpt-5-4 and cause pricing lookup misses.

Restrict the dot-to-hyphen substitution in normalizeCopilotModel to
names that begin with 'claude-', which are the only Copilot-emitted
IDs that need normalization. All other model names pass through
unchanged.

Add TestNormalizeCopilotModel table test covering claude variants,
gpt-5.4/gpt-5.5, gpt-4o, o3-mini, and the empty string.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 2 people

internal/parser/copilot.go

@@ -290,13 +290,17 @@ func formatCopilotToolCalls(
 }
 
 // normalizeCopilotModel converts the model identifier used in
-// Copilot session events (dots in version numbers, e.g.
-// "claude-sonnet-4.6") to the form used in the pricing catalog
-// (hyphens, e.g. "claude-sonnet-4-6"). Only dots that follow a
-// digit and precede a digit are replaced to avoid mangling
-// non-version dots in other model names.
+// Copilot session events to the form used in the pricing catalog.
+// Claude model IDs use dots in version numbers in Copilot events
+// (e.g. "claude-sonnet-4.6") but hyphens in the pricing catalog
+// (e.g. "claude-sonnet-4-6"). Other model families such as GPT
+// already use dots in the catalog (e.g. "gpt-5.4"), so only
+// claude-prefixed names are normalized.
 func normalizeCopilotModel(model string) string {
-	return strings.ReplaceAll(model, ".", "-")
+	if strings.HasPrefix(model, "claude-") {
+		return strings.ReplaceAll(model, ".", "-")
+	}
+	return model
 }
 
 // readCopilotWorkspaceName reads the session name from the

internal/parser/copilot_test.go

@@ -506,6 +506,28 @@ func TestParseCopilotSession_ModelReset(t *testing.T) {
 	assertEqual(t, "", msgs[3].Model, "msgs[3].Model (reset)")
 }
 
+func TestNormalizeCopilotModel(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"claude-sonnet-4.6", "claude-sonnet-4-6"},
+		{"claude-haiku-4.5", "claude-haiku-4-5"},
+		{"claude-opus-4.7", "claude-opus-4-7"},
+		// GPT models use dots in the pricing catalog and must not be changed.
+		{"gpt-5.4", "gpt-5.4"},
+		{"gpt-5.5", "gpt-5.5"},
+		{"gpt-4o", "gpt-4o"},
+		{"o3-mini", "o3-mini"},
+		{"", ""},
+	}
+	for _, tc := range tests {
+		t.Run(tc.input, func(t *testing.T) {
+			assert.Equal(t, tc.want, normalizeCopilotModel(tc.input))
+		})
+	}
+}
+
 func TestSessionIDFromPath(t *testing.T) {
 	tests := []struct {
 		path string