chore: import upstream snapshot with attribution

packages/trigger-sdk/CLAUDE.md

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+# Trigger.dev SDK
+
+`@trigger.dev/sdk` - the main customer-facing SDK for writing background tasks.
+
+## Import Rules
+
+Always import from `@trigger.dev/sdk`. Never use `@trigger.dev/sdk/v3` (deprecated path alias).
+
+## Key Exports
+
+- `task` - Define a background task
+- `schedules.task` - Define a scheduled (cron) task
+- `batch` - Batch trigger operations
+- `runs` - Run management and polling
+- `wait` - Wait for events, delays, or other tasks
+- `retry` - Retry utilities
+- `queue` - Queue configuration
+- `metadata` - Run metadata access
+- `logger` - Structured logging
+
+## When Adding Features
+
+1. Implement the feature in the SDK
+2. Test with the `hello-world` project in the [`triggerdotdev/references`](https://github.com/triggerdotdev/references) repo
+3. Docs updates (`docs/`) are usually done in a separate PR
+
+Do NOT update `rules/` or `.claude/skills/trigger-dev-tasks/` unless explicitly asked. These are maintained in separate dedicated passes.