fix(run): synthesize DevTools URL from VM service URI

[jainam-bhavasar]

Why

Closes #43.

flutter run --machine reliably emits the VM Service URI via app.debugPort, but it does not always print a human-readable DevTools URL. Today the d keybind depends entirely on capturing app.devTools: <url> from Flutter output. When that line never arrives, the shortcut reports "DevTools not ready" even though memory polling, network polling, and the VM Service itself are all healthy.

What

• New vm_service_uri slot on DeviceSession — stores the last VM Service URI from AppStarted / app.debugPort.
• send_devtools_serve() — asks the Flutter daemon to serve DevTools; the {"result":{"host":"…","port":…}} response is parsed by parse_daemon_line and surfaced as an app.devToolsServer: debug log.
• Synthesize the DevTools URL — after AppStarted, probe localhost ports 9100–9199 for an already-running DevTools server. If none is found, send devtools.serve and poll until the server appears.
• Last-resort probe in open_devtools_all — if d is pressed after the startup window, one more probe + daemon request before showing the warning.
• Parse both DevTools URL forms — the structured app.devTools: <url> prefix and the human-readable "Flutter DevTools … is available at: <url>" sentence.
• app.debugPort field priority — check devToolsUrl and url before wsUri / uri so newer Flutter SDK fields are picked up.

No new workspace dependency — url is already declared in the root Cargo.toml.

How to test

cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace --locked

Live:

# Kill any leftover DevTools/DDS processes for a clean test
pkill -f "dart devtools --no-launch-browser" || true
pkill -f "dds_aot.dart.snapshot" || true

# Run
target/debug/flutter-cli run -d emulator-5554 --no-picker --no-wifi --no-tui \
  -- -t lib/main.dart --flavor staging --dart-define env=dev

Expected output after AppStarted:

app.devTools: http://127.0.0.1:9100/?uri=http%3A%2F%2F127.0.0.1%3A58565%2F…
VM Service ready

Files changed

File	What
crates/fl-flutter/src/daemon.rs	send_devtools_serve() method
crates/fl-flutter/src/parse.rs	Parse devtools.serve response, wider app.debugPort field lookup
crates/flutter-cli/Cargo.toml	url.workspace = true
crates/flutter-cli/src/multi.rs	VM URI slot, URL synthesis helpers, fallback chain, 11 new tests

[Antoinegtir]

Thanks for digging into this — issue #43 is real, and the core idea (parse the devtools.serve response + widen the app.debugPort field lookup) is the right one. I rebased it locally on current master and it builds + the full test suite passes, so the foundation is solid.

Before I can merge, a few things need to change. The PR is quite a bit heavier than the fix needs to be, and master has since gained a helper that overlaps with this PR. Details inline — happy to merge once these are addressed. 🙏

[Antoinegtir]

Matching the JSON-RPC response by its {host, port} shape instead of the request id is fragile — the comment above even acknowledges it. devtools.serve is sent with id:2 (and app.restart already uses id:1), so please key the response on obj.get("id") == 2 and only fall back to the shape check if the id is absent. As written, any future daemon response that happens to carry {host, port} gets mis-tagged as a DevTools server.

[Antoinegtir]

Re-emitting a synthetic app.devTools: <url> Log event just so the existing string-match loop picks it up is a workaround stacked on a workaround. You already hold devtools_slot in this scope — set it directly (*devtools_slot.lock().await = Some(devtools_uri)) instead of round-tripping through a fake log line. That also removes one of the (currently four) code paths that can write that slot, which makes the races easier to reason about.

[Antoinegtir]

Scanning 100 ports sequentially with a 50 ms timeout each means a d keypress can block for up to ~5 s before it shows "not ready" — today that path is instant. Please drop the brute-force scan: the devtools.serve daemon response already hands you the exact host+port, so the synthesis path doesn't need to guess. If you want to keep any probe at all, bound it hard (a couple of ports, sub-second total) and keep it off the keypress path.

[Antoinegtir]

master now has ws_uri_to_http in crates/fl-tui/src/runner.rs (added for the IntelliJ auto-attach feature) that does exactly this ws/wss → http conversion + /ws strip. Please don't add a second copy — lift one shared helper into fl-core (or fl-flutter) and call it from both crates. Two independent implementations of the same URL surgery will drift apart.