docs: add TypeScript examples for retry strategies

[nol4lej]

Description

Add TypeScript code examples to replace // Not supported in TypeScript and
// This feature is not yet available in TypeScript SDK placeholders in
retry-strategies.mdx and hooks.mdx.

Changes:

• Add retry-strategies.ts with three snippet sections:

  • customizing_retry — exponential backoff using AfterModelCallEvent and ModelThrottledError
  • disabling_retry — explanation that TypeScript has no built-in retry mechanism
  • custom_retry_logic — custom retry logic via event.retry = true

• Update hooks.ts with three plugin class examples:

  • RetryOnServiceUnavailable — retries on ServiceUnavailableException with exponential backoff
  • PropagateUnexpectedExceptions — re-throws non-allowlisted errors from tool calls
  • RetryOnToolError — retries failed tool calls tracking attempts per toolUseId

• Update retry-strategies.mdx and hooks.mdx to use snippet inclusions in the existing TypeScript tabs

Type of Change

• Content update/revision

Checklist

• I have read the CONTRIBUTING document
• My changes follow the project's documentation style
• I have tested the documentation locally using npm run dev
• Links in the documentation are valid and working

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[nol4lej]

correct