[lchoquel]

Adds SyncPipelexAPIClient (pipelex_sdk/sync_client.py), a synchronous facade over PipelexAPIClient, so a script, a batch job or a Django view calls every method without await or an asyncio.run wrapper of its own. It wraps and delegates to one private async client on a daemon event-loop thread rather than adding a second transport, so the connection pool stays warm and one instance can be shared across threads; a call from inside a running event loop raises the new SyncClientInEventLoopError before anything is sent. A parity test pins each sync method's signature to its async twin in both directions, and the docs, README and changelog describe the facade.

Closes L-260907-91b052

🤖 Generated with Claude Code

[lchoquel]

Review round 1: profile 4 (deep), bar open.

Reviewers that produced a review: cubic, Codex (review), Codex (adversarial), code-review at high, and gstack's review. gstack's report says it skipped its own Codex passes.

Fixed in c742052, each with a regression test that fails on the previous code:

• A call made while close() ran started a second loop on the HTTP client the first loop was still closing. close() now holds the facade's lock until the old loop is gone.
• A KeyboardInterrupt or SystemExit raised on the loop, such as an on_poll callback calling sys.exit(), stopped the loop and left the caller and close() blocked for good. Both now reach the caller, and the loop survives.
• Ctrl+C during a page fetch surfaced as RuntimeError('aclose(): asynchronous generator is already running') instead of the interrupt.
• A paged iterator left open across close() ended silently. It now raises concurrent.futures.CancelledError.
• An abandoned iterator collected by the garbage collector while its facade held the lock deadlocked. The lock is now reentrant.
• A partly read iterator left in a module global kept the interpreter from exiting.
• The in-loop refusal named the wrapped coroutine instead of the facade method that was called.

Fixed in d0c0fbc: the parity test also pins that every twin forwards each argument and hands back the result. A twin dropping an argument used to pass the whole suite.

Deferred:

• A facade dropped without close() keeps its loop thread and descriptors until the process exits: L-260912-a5f857.
• A facade used in a forked child blocks forever: L-260912-166b5f.

[lchoquel]

Closing unmerged. The two review rounds showed that sharing one facade across threads through a background event loop does not converge, so the facade will be rebuilt on asyncio.Runner, one facade per thread, in Pipelex/pipelex-sdk once the SDKs move there, rather than re-applied from this branch. The branch is kept as a reference. Tracked as L-260907-91b052; the Python 3.11 cancellation bug in wait_for_result that round 2 surfaced is fixed separately as L-261001-3aae86.