Update claude-api skill: auth, cloud providers, Managed Agents fixes, token counting (#1276)

* Sync claude-api skill with latest upstream updates

- Add token-counting.md and SKILL.md trigger description update
- Add auth guidance: env credential resolution, ant auth login, OAuth/WIF doc links, 401 causes
- Add mid-conversation system messages (beta) to prompt-caching, agent-design, SKILL.md, Python/TS READMEs
- Add cache pre-warming (max_tokens: 0) section to prompt-caching
- Add Managed Agents pre-flight viability check to onboarding and overview
- Add Bedrock model-ID section to model-migration; add Bedrock row to live-sources
- Add /claude-api migrate subcommand row and migrate-entry callout
- Fix MA networking config: limited type with allow_package_managers/allow_mcp_servers
- Bump MA create-operations rate limit to 300 RPM
- Fix MA SDK drift: sessions.events.stream(), event.name, typed event arrays
- Add SDK coverage: stop_details, error .type, C# tool runner + MA support, Go model constants, Java 2.34.0, client config, response helpers, auto-pagination, advisor tool
- Move Sonnet 4 / Opus 4 to deprecated in models.md

* Add Anthropic CLI and Claude Platform on AWS docs to claude-api skill

- Add shared/anthropic-cli.md: install, auth profiles, OAuth scopes, command
  structure, version-controlled Managed Agents resources, credential traps
- Add shared/claude-platform-on-aws.md: AnthropicAWS clients, SigV4 auth,
  workspace_id, regions, feature availability
- Restore cross-references to both files throughout SKILL.md and the
  managed-agents docs (previously rewritten to live-sources.md pointers)
- Restore Claude Platform on AWS provider taxonomy in SKILL.md, the
  migration-guide section, and live-sources rows

skills/claude-api/ruby/claude-api.md

@@ -111,3 +111,30 @@ message = client.messages.create(
 For 1-hour TTL: `cache_control: { type: "ephemeral", ttl: "1h" }`. There's also a top-level `cache_control:` on `messages.create` that auto-places on the last cacheable block.
 
 Verify hits via `message.usage.cache_creation_input_tokens` / `message.usage.cache_read_input_tokens`.
+
+---
+
+## Stop Details
+
+When `stop_reason` is `:refusal`, the response includes structured `stop_details`:
+
+```ruby
+if message.stop_reason == :refusal && message.stop_details
+  puts "Category: #{message.stop_details.category}"     # :cyber, :bio, or nil
+  puts "Explanation: #{message.stop_details.explanation}"
+end
+```
+
+---
+
+## Error Type
+
+`APIStatusError` exposes a `.type` field for programmatic error classification:
+
+```ruby
+begin
+  client.messages.create(...)
+rescue Anthropic::APIStatusError => e
+  puts e.type  # :rate_limit_error, :overloaded_error, etc.
+end
+```