Update claude-api skill: Managed Agents July launch wave, partner pricing, tool-runner corrections (#1463)

Syncs the claude-api skill with the current upstream source.

## Managed Agents — five new features

- `effort` on the agent's `model` object (a level string or `{"type": "<level>"}`).
  It is agent-configuration only: setting it in a per-session `model` override is
  silently ignored.
- Optional `version` on agent update, for optimistic concurrency. Omit it for
  last-write-wins.
- `initial_events` on session create, collapsing create plus first send into one
  call. Validation is all-or-nothing and only `user.message` and
  `user.define_outcome` are accepted.
- Environment and memory-store webhooks: four `environment.*` events and three
  `memory_store.*` events.
- Event deltas on per-thread streams. Previews are thread-scoped, so a child
  thread's previews never reach the session-level stream.

## Corrections to behavior the skill already documented

- Tool output offload triggers at 100,000 characters (~25k tokens), not 100K
  tokens, and covers built-in tools rather than MCP alone.
- `system.message` works on four models, checks only the primary model, appends
  system context instead of replacing the prompt, and is accepted during a
  `requires_action` idle when it trails a tool result in the same request.
- Vault-to-MCP credential matching is normalized (scheme and host lowercased,
  default ports and trailing slashes stripped), not byte-exact.
- Multiagent depth greater than 1 is a validation error, not silently ignored.
- Outcome `interrupted` fires even when evaluation never started, and then
  carries an empty-string `outcome_evaluation_start_id`.
- Deployment jitter is 15% of the run interval, floor 5s, cap 9 minutes.
- Webhooks retry three times with jittered 5-120s backoff, then drop silently.
  Auto-disable is duration-based with three named triggers.
- `session.status_terminated` means completion or error.
- `agent.thinking` is a progress signal and carries no thinking content.
- `processed_at` is already populated on first sighting for
  `user.define_outcome`, `user.custom_tool_result`, and `user.tool_result`.
- Session creation does not provision the sandbox.
- Skill `version` applies to Anthropic-authored skills too.
- Console-created vault credentials are header-injection only, and vault
  environment-variable substitution skips secrets in URL paths.
- Console trace URLs need the real workspace ID when the API key is not in the
  Default workspace.

## Elsewhere in the skill

- Note partner pricing under the first-party price table: Microsoft Foundry
  bills at standard API rates, while Amazon Bedrock and Vertex AI are
  partner-operated with separate pricing.
- Correct the tool-runner human-in-the-loop guidance, which previously pointed
  readers at the manual loop for approval gates the runner's per-turn hooks
  already cover.
- Repoint links away from the retired documentation hosts.
- Dedupe eagerly loaded SKILL.md content that the per-section files already
  cover.

skills/claude-api/shared/managed-agents-environments.md

@@ -61,7 +61,7 @@ To run tool execution in **your own infrastructure** instead of Anthropic's, set
 
 ## Resources
 
-Attach files, GitHub repositories, and memory stores to a session. **Session creation blocks until all resources are mounted** — the container won't go `running` until every file and repo is in place. Max **999 file resources** per session. Multiple GitHub repositories per session are supported. For `type: "memory_store"` resources (persistent cross-session memory — max 8 per session), see `shared/managed-agents-memory.md`.
+Attach files, GitHub repositories, and memory stores to a session. Resources are resolved during session creation, so a bad `file_id` or an unreachable repo surfaces on the create call rather than mid-run. Creating a session does **not** by itself start work or provision the sandbox — without `initial_events` the session is only registered, and the sandbox comes up when the session first needs it (see `shared/managed-agents-core.md` → Seeding a session with `initial_events`). Max **999 file resources** per session. Multiple GitHub repositories per session are supported. For `type: "memory_store"` resources (persistent cross-session memory — max 8 per session), see `shared/managed-agents-memory.md`.
 
 ### File Uploads (input — host → agent)