Propagate parent env to MCP server subprocess (#18)

The mcp SDK's StdioServerParameters does not pass the parent
process's environment to the spawned server by default, so env
vars set on the CLI process (notably MARCHWARDEN_MODEL) were
silently dropped on the way to the researcher.

Pass env=os.environ.copy() to StdioServerParameters so the server
sees the same environment as the CLI. Also update scripts/docker-test.sh
to forward MARCHWARDEN_MODEL into the container and to detect a
non-TTY parent so non-interactive `ask` invocations don't fail with
"the input device is not a TTY".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cli/main.py

@@ -40,6 +40,7 @@ async def call_research_tool(
     params = StdioServerParameters(
         command=sys.executable,
         args=["-m", "researchers.web.server"],
+        env=os.environ.copy(),
     )
     async with stdio_client(params) as (read, write):
         async with ClientSession(read, write) as session:

scripts/docker-test.sh

@@ -31,7 +31,13 @@ case "$cmd" in
       exit 1
     fi
     mkdir -p "$HOME/.marchwarden/traces"
-    docker run --rm -it \
+    tty_flag=""
+    if [ -t 0 ] && [ -t 1 ]; then tty_flag="-it"; fi
+    env_flag=""
+    if [ -n "${MARCHWARDEN_MODEL:-}" ]; then
+      env_flag="-e MARCHWARDEN_MODEL=$MARCHWARDEN_MODEL"
+    fi
+    docker run --rm $tty_flag $env_flag \
       -v "$ROOT:/app" \
       -v "$HOME/secrets:/root/secrets:ro" \
       -v "$HOME/.marchwarden:/root/.marchwarden" \