feat(pricing): add Claude Opus 5 to built-in model pricing table

Seed claude-opus-5 at $5/$25 per MTok with $0.50 cache read and $6.25
cache creation, matching the Opus 4.8 tier. Verified against models.dev
and the official Anthropic models overview. Fast mode ($10/$50) is a
separate billing path and is deliberately left out of the table.

New model id, so seed only; no repair entry and no SCHEMA_VERSION bump.

src-tauri/src/database/schema.rs

@@ -1545,6 +1545,8 @@ impl Database {
                 "1.00",
                 "12.50",
             ),
+            // Claude Opus 5（与 Opus 4.8 同价位；fast mode $10/$50 不入表）
+            ("claude-opus-5", "Claude Opus 5", "5", "25", "0.50", "6.25"),
             // Claude 4.8 系列
             (
                 "claude-opus-4-8",