…mple

Adds a Python port of @cloudflare/dynamic-workflows alongside the existing
JS package, and an interactive browser playground example mirroring
examples/basic.

`packages/dynamic-workflows-py/`:

  * Pure-Python `_core` module exporting the envelope helpers
    (`_wrap_params`, `_unwrap_params`, `MissingDispatcherMetadataError`),
    `dispatcher_binding_impl`, and `dispatch_workflow_core`. No `js` /
    `workers` / `pyodide.ffi` imports so the helpers are host-testable.
  * `_workerd` module with the workerd/Pyodide-bound layer:
    `DynamicWorkflowBinding` (a single `WorkerEntrypoint` subclass minted
    by `wrap_workflow_binding`), `create_dynamic_workflow_entrypoint`,
    `dispatch_workflow`, and `WrappedWorkflow` / `WrappedInstance` tenant
    facades. `create()` returns a plain JS object literal
    `{id, status, pause, resume, terminate, restart, sendEvent}` with
    methods bound to the underlying JS WorkflowInstance via
    `Function.prototype.bind` — sync `.id`, RPC-callable method
    handles, no second WorkerEntrypoint class, no factory ceremony for
    instance handles.
  * `__init__.py` falls back to the `_core`-only surface when imported
    outside the Pyodide runtime, so host pytest doesn't need import shims.
  * 40 host pytest tests covering envelope wrap/unwrap, the binding-impl
    contract (mirrors JS `binding.test.ts`), and the dispatch-core flow
    (mirrors JS `entrypoint.test.ts`).

`examples/python/`:

  * Interactive playground dispatcher with the same UX as
    `examples/basic`: editor + payload + step timeline + status polling.
    SSE log streaming is omitted (no Python streaming-tail story yet);
    progress is driven by polling `/api/status/:runId`.
  * Demonstrates **both** trigger shapes, switchable in the dashboard UI:
      - **tenant**: dispatcher RPCs into the tenant's
        `Default.start_workflow()`, which calls `env.WORKFLOWS.create()`
        from the tenant's own context. Models the multi-tenant SaaS case
        where the tenant code is what triggers workflows.
      - **direct**: dispatcher calls `wrap_workflow_binding(metadata).create()`
        directly. The tenant only needs `TenantWorkflow(WorkflowEntrypoint)`
        — no `Default(WorkerEntrypoint)` required.
  * Per-run tenant source ships with the dispatcher metadata so workflow
    replays survive isolate recycles without a Durable Object.
  * Verified end-to-end against `pywrangler dev`: both modes complete the
    full Dashboard → dispatcher → tenant → @step.do chain.

Workspace plumbing:

  * Repo-root `pyproject.toml` declares a uv workspace with both Python
    packages as members.
  * `examples/python/pyproject.toml` resolves `dynamic-workflows` via
    `[tool.uv.sources] dynamic-workflows = { workspace = true }`. The
    `workers-py` and `workers-runtime-sdk` deps are pinned to a fork
    commit that patches `pywrangler sync` to honor uv workspaces /
    sources (upstream PR cloudflare/workers-py#107). No pre-built
    wheels or `find-links` config needed.
  * `.gitignore` updated with the standard Python / uv / pywrangler /
    pytest / linter artifacts.