fix: v0.2.6 — trigger_build_stream truly fire-and-forget

Claude Desktop times out tool calls after ~4 minutes. The previous
implementation read the first SSE chunk before returning, which could
block for the entire image-pull duration.

Now: send the GET request, wait for HTTP response headers (status
check only), close the connection immediately — never read SSE events.
DSM starts the build on receipt of the request and continues
server-side. ReadTimeout on headers is caught and ignored (request
already sent). Removes the _json import added in 0.2.5.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,18 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.2.6] - 2026-04-21
+
+### Fixed
+
+- `DsmClient.trigger_build_stream`: Claude Desktop aborts tool calls after
+  ~4 minutes. The previous implementation read the first SSE chunk before
+  returning, which could block for the entire duration of an image pull.
+  Fixed by making the call truly fire-and-forget: the HTTP request is sent,
+  response headers are received (HTTP status check only), then the connection
+  is closed immediately without reading any SSE events. DSM continues the
+  build server-side regardless. The `_json` import added in 0.2.5 is removed.
+
 ## [0.2.5] - 2026-04-21
 
 ### Changed