fix(kiro): deliver system prompt natively, add Opus 4.5/4.7/4.8, tolerate dash version ids (#2366)

- Pass system prompt via native systemInstruction field (+ <instructions> fallback)
  so Claude models stop treating it as info-only <system-reminder>
- Add Opus 4.5/4.7/4.8 (base/thinking/agentic/thinking+agentic) to Kiro registry
- normalizeModelId(): dash->dot version separator, scoped to Kiro provider only
- Replace <system-reminder> with <instructions> in claude-to-openai/openai-to-kiro

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/providers/models/schema.js

@@ -1,5 +1,14 @@
 import { deriveModelName } from "./namePatterns.js";
 
+// Normalize version separators in a model id: hyphen between two digits becomes a dot.
+// Registry ids use dots for versions ("claude-sonnet-4.5") but clients (CLIs, aliases)
+// often send them with dashes ("claude-sonnet-4-5"). Only digit-digit hyphens are
+// touched, so word/suffix hyphens stay intact ("-thinking", "-agentic", "qwen3-coder-next").
+export function normalizeModelId(modelId) {
+  if (typeof modelId !== "string") return modelId;
+  return modelId.replace(/(\d)-(\d)/g, "$1.$2");
+}
+
 // Model defaults centralized (was scattered as `m.kind || "llm"`, `quotaFamily || "normal"`, etc.)
 export const MODEL_DEFAULTS = {
   kind: "llm",