v2.9.0

## Features

### Disable outbound HTTP requests from modules

Standalone operators can now disable module-originated HTTP requests with the `[module-http] enabled = false` configuration setting. This provides an explicit deployment-level control for environments where modules should not be allowed to access external HTTP services.

([#5774](<https://github.com/clockworklabs/SpacetimeDB/pull/5774>))

### Improved .NET version and host OS handling

`spacetime init` and `spacetime dev` now choose a compatible .NET target based on the host OS: .NET 10 on Windows and Linux, and .NET 8 on macOS. C# build, generation, development, and publish commands now report incompatible host and .NET combinations clearly. This also fixes duplicate package references in .NET 8 NativeAOT module projects.

([#5571](<https://github.com/clockworklabs/SpacetimeDB/pull/5571>))

## Bug Fixes

### Preserve acknowledged transactions across commitlog maintenance

Commitlog segment rotation and compression now durably sync newly installed segment files and their containing directory. Previously, a power loss in a narrow window after a segment was renamed could lose transactions that had already been acknowledged as durable; compression could similarly replace a durable segment without fully persisting the replacement. The updated persistence path preserves the confirmed-read durability guarantee across crashes.

([#5785](<https://github.com/clockworklabs/SpacetimeDB/pull/5785>))

### TypeScript SDK preserves identity during automatic reconnect

The TypeScript SDK now reuses the identity token issued during a first-time anonymous connection when automatically reconnecting. Previously, if the initial connection was created without a stored token, a later reconnect could request a new anonymous identity and silently lose access to data associated with the original identity. Explicit connection rebuilds can still change identity as intended.

([#5761](<https://github.com/clockworklabs/SpacetimeDB/pull/5761>))

### Improve WebSocket liveness and idle timeout handling

Any client data now counts as WebSocket activity and extends the idle deadline, rather than requiring a pong specifically. Idle connections are closed with a proper close handshake and an `idle timeout` reason, with a grace period before forced teardown. This improves liveness detection and gives clients a clear reason for disconnection.

([#5517](<https://github.com/clockworklabs/SpacetimeDB/pull/5517>))

### Fix C++ index queries with three or more columns

C++ multi-column index scans now correctly support exact prefixes followed by an optional terminal range across indexes with three or more columns. Invalid queries with a non-terminal range are rejected at compile time, and index iterator buffering now handles large result payloads correctly.

([#5565](<https://github.com/clockworklabs/SpacetimeDB/pull/5565>))

### Fix Unity static state reset and WebGL builds

The C# SDK now resets generated generic table-handle static state through a non-generic Unity initialization path, fixing Play Mode behavior when domain reload is disabled. The missing `IEnumerator` import used by Unity WebGL message parsing has also been restored.

([#5738](<https://github.com/clockworklabs/SpacetimeDB/pull/5738>), [#5792](<https://github.com/clockworklabs/SpacetimeDB/pull/5792>))

### Clean up SDK state after errors and disconnections

The C# SDK now clears outstanding request tracking and pending operations when connections fail, removes failed subscriptions, and rejects one-off queries immediately when disconnected. This prevents stale state and memory from accumulating across error and reconnect paths.

([#5794](<https://github.com/clockworklabs/SpacetimeDB/pull/5794>))

## What's Changed

- Add configuration for disabling module outbound HTTP requests in [#5774](<https://github.com/clockworklabs/SpacetimeDB/pull/5774>)
- Improve WebSocket liveness checks and idle timeout handling in [#5517](<https://github.com/clockworklabs/SpacetimeDB/pull/5517>)
- Preserve acknowledged transactions across commitlog rotation and compression in [#5785](<https://github.com/clockworklabs/SpacetimeDB/pull/5785>)
- Improve .NET version and host OS handling in [#5571](<https://github.com/clockworklabs/SpacetimeDB/pull/5571>)
- Preserve TypeScript client identity tokens during automatic reconnect in [#5761](<https://github.com/clockworklabs/SpacetimeDB/pull/5761>)
- Fix Unity static state resetting for generic types in [#5738](<https://github.com/clockworklabs/SpacetimeDB/pull/5738>)
- Fix Unity WebGL `IEnumerator` import in [#5792](<https://github.com/clockworklabs/SpacetimeDB/pull/5792>)
- Clean up C# SDK state after errors and disconnections in [#5794](<https://github.com/clockworklabs/SpacetimeDB/pull/5794>)
- Fix C++ multi-column queries with three or more columns in [#5565](<https://github.com/clockworklabs/SpacetimeDB/pull/5565>)

**Full Changelog**: [v2.8.3...v2.9.0](<https://github.com/clockworklabs/SpacetimeDB/compare/v2.8.3...release/candidate/v2.9.0>)