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/shared/live-sources.md

@@ -46,6 +46,9 @@ This file contains WebFetch URLs for fetching current information from platform.
 | Token Counting   | `https://platform.claude.com/docs/en/build-with-claude/token-counting.md`   | "Extract token counting API usage and examples"                                                         |
 | Rate Limits      | `https://platform.claude.com/docs/en/api/rate-limits.md`                    | "Extract current rate limits by tier and model"                                                         |
 | Errors           | `https://platform.claude.com/docs/en/api/errors.md`                         | "Extract HTTP error codes, meanings, and retry guidance"                                                |
+| Amazon Bedrock   | `https://platform.claude.com/docs/en/build-with-claude/claude-on-amazon-bedrock.md` | "Extract the AnthropicBedrockMantle client per language, `anthropic.`-prefixed model IDs, auth paths, feature availability, and regions" |
+| Claude Platform on AWS | `https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws.md` | "Extract the AnthropicAWS client per language, SigV4 auth, credential precedence, short-term API keys, workspace_id, and region requirements" |
+| Claude Platform on AWS — IAM actions | `https://platform.claude.com/docs/en/api/claude-platform-on-aws-iam-actions.md` | "Extract the IAM action names, resource ARNs, and policy examples required for each API capability" |
 
 ### Tools
 
@@ -107,6 +110,8 @@ The `ant` CLI provides terminal access to the Claude API. Every API resource is
 | Topic         | URL                                                     | Extraction Prompt                                                                                  |
 | ------------- | ------------------------------------------------------- | -------------------------------------------------------------------------------------------------- |
 | Anthropic CLI | `https://platform.claude.com/docs/en/api/sdks/cli.md`   | "Extract CLI install, authentication, command structure, and the beta:agents/environments/sessions commands" |
+| Authentication overview | `https://platform.claude.com/docs/en/manage-claude/authentication.md` | "Extract the credential options (API keys, interactive OAuth login, Workload Identity Federation) and when to use each" |
+| WIF reference | `https://platform.claude.com/docs/en/manage-claude/wif-reference.md`  | "Extract credential precedence order, the profile configuration file schema, and the configuration directory layout" |
 
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