fix(ci): switch timing from OTEL receiver to --progress=plain pipe filter

Dagger v0.20.8 only supports 'grpc' and 'http/protobuf' OTLP protocols;
'http/json' triggers a WARN and exports nothing.  The new approach pipes
dagger's --progress=plain output through a Python script that echoes it
in real-time and prints a timing table at EOF.  No HTTP server, no port
files, no protocol issues — works locally and in CI.

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

Taskfile.yml

@@ -252,29 +252,18 @@ tasks:
       - dagger call --progress=plain -q -m ci --source=. publish-website --ssh-key env:SSH_PRIVATE_KEY --ssh-user "$SSH_USER" --ssh-host "$SSH_HOST"
 
   check-dagger:
-    desc: Run full check suite via Dagger (with OTEL timing report if python3 is available)
+    desc: Run full check suite via Dagger (with timing report if python3 is available)
     cmds:
       - |
         if ! command -v python3 >/dev/null 2>&1; then
           dagger call --progress=plain -q -m ci --source=. check
           exit $?
         fi
-        PORTFILE=$(mktemp)
-        python3 ci/otelrecv.py --port-file="$PORTFILE" &
-        RECV_PID=$!
-        cleanup() {
-          kill "$RECV_PID" 2>/dev/null
-          wait "$RECV_PID" 2>/dev/null
-          rm -f "$PORTFILE"
-        }
-        trap cleanup EXIT
-        until [ -s "$PORTFILE" ]; do sleep 0.05; done
-        PORT=$(cat "$PORTFILE")
-        RC=0
-        OTEL_EXPORTER_OTLP_ENDPOINT="http://127.0.0.1:$PORT" \
-        OTEL_EXPORTER_OTLP_PROTOCOL="http/json" \
-        dagger call --progress=plain -q -m ci --source=. check || RC=$?
-        exit $RC
+        RC_FILE=$(mktemp)
+        (dagger call --progress=plain -q -m ci --source=. check; echo $? >"$RC_FILE") 2>&1 | python3 ci/otelrecv.py
+        RC=$(cat "$RC_FILE" 2>/dev/null || echo 1)
+        rm -f "$RC_FILE"
+        exit "$RC"
 
   integration-android:
     desc: UI integration tests on a connected Android emulator (Stalwart on host, emulator reaches it via 10.0.2.2)