test(web): omit throughput for zero-duration skill seed

The normalized embedded stream in the skill seed contains no positive decode interval. Its rendered metrics correctly omit throughput rather than invent a rate. Refresh only the owning ARIA expectation after the full Web lane isolated this final mismatch; user/model/skill content and metric calculation remain unchanged.

Validation: owning refresh and subsequent read-only browser replay pass. The preceding full Web run had only this one expectation mismatch.

snapshots/web/skill-tool-row/ui.expected.md

@@ -61,4 +61,4 @@
   - text: DeepSeek-V4-Flash
   - img
 - button "Send message" [disabled]
-- text: 1 turns · 2 steps LLM {{duration}} · Tool call {{duration}} TTFT avg {{duration}} · {{throughput}} tok/s Cache hit 0% Input 280 tok · Output 30 tok
+- text: 1 turns · 2 steps LLM {{duration}} · Tool call {{duration}} TTFT avg {{duration}} Cache hit 0% Input 280 tok · Output 30 tok