To my knowledge a force close can take up to 2 weeks to settle fully. So, maybe some patience is needed.
I believe the Electrum is legit from electrum.org
I wouldn't care much about this code signing certificate. There's a thread in this forum section which describes meticulously how to check if your Electrum version is genuine.
The scenario was I opened a trampoline routing channel with tick "Use trampoline routing (disable gossip)", the channel was opening, I choose "Electrum trampoline" with 0.01 btc, tapped "OK",
the channel was opening,
This is not reflected in the funding transaction of the channel which looks a little bit strange to me.
You have to make all the choices before you click OK to open the channel. The way you describe that is different.
Did you wait until the status changed from OPENING to OPEN? This takes at least 3 confirmations on the blockchain.
I tried to send money to a merchant with lightning code in "Send", it's about 0.001 btc, then tapped "pay", Electrum shown "No path found", I thought somethings wrong, so I go back to Channel tapped "Close Channel", no response, then tapped "Force close channel" repeatly for both options, then the channel goes from "opening" to "funded", then got stuck here.
This sounds to me you're acting too hasty, especially the channel closing part.
"No path found" means your channel partner couldn't find a route to forward your LN payment to your merchant. With the single channel you opened there's no way to proceed from here with success (or it's beyond your control) unless you open another channel (additionally or not). You would need some other channel to a better connected node which may be able to find a route. But to my knowledge there's no easy way to find such a channel partner. Likely a channel partner who has lots of channels open should find a successful route to your merchant, but there's no guarantee.
Closing a channel may not give an immediate response. Be more patient. A cooperative Close needs both sides to agree to publish a channel finalization settlement transaction on-chain which needs at least 3 confirmation, too. But Electrum should indicate this somehow with a channel status of "CLOSING".
Choosing "Force close" might not have been necessary as this should be a last resort option if the channel partner is non-responsive. But I would wait some time after a normal close to see what's going on.
Do you remember at which point of your closing massaker you got the error message that you should enable "gossip routing"?
As @nc50lc said, I too have no further help for you. I'm not sure how Electrum should indicate that a Force close is in progress. You should try to resolve this in the Github issue. There are some strange issues with your channel, indeed.