Document TaskStream boards in the README and .env.example

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.env.example

@@ -186,3 +186,18 @@ GIT_SYNC_CRON=hourly
 GIT_SYNC_TTL=55
 GIT_MAX_ISSUES=25
 GIT_HTTP_TIMEOUT=15
+
+###############################################################################
+# TaskStream — the issue tracker
+###############################################################################
+# `taskstream: true` on POST /v1/projects opens a public board there too.
+# Both default to production.
+TASKSTREAM_API_URL=https://api.taskstream.pireon.dev
+TASKSTREAM_WEB_URL=https://taskstream.pireon.dev
+
+# A Pireon personal access token (oauth.pireon.dev/tokens), only used when the
+# caller signs in with a machine token (pmt_…), which TaskStream cannot read.
+# People with a Pireon token have theirs passed on instead. Empty: machine
+# tokens cannot ask for a board.
+TASKSTREAM_TOKEN=
+TASKSTREAM_HTTP_TIMEOUT=10