Refactoring complete: v0.4.0 architectural milestone (#1)

## Summary

Completed Phase 5 refactoring and reached the target architecture.

**Architectural milestone achieved:**
- Service layer owns all state and is the sole writer
- UI is a thin Fyne view, all widget updates marshaled via `fyne.Do`
- Core engines are stateless and injectable
- Domain types are pure (no `yaml:"-"` fields)
- Full module builds and `go vet ./...` clean

## Changes

- Bump version: 0.3.6 → 0.4.0
- Update CHANGELOG with Phase 5 summary
- Add ROADMAP "Refactoring Follow-Ups" section

## Known follow-up work

1. **Linux test build broken** — `runner_test.go` needs `//go:build windows` tag
2. **File-size limits exceeded** — `operations.go` (486 lines), `jobs_view.go` (415 lines)

See ROADMAP.md for details.

---------

Co-authored-by: mixeme <mix.public@ya.ru>
Reviewed-on: #1

docs/ROADMAP.md

@@ -2,6 +2,32 @@
 
 This file tracks planned GoSentry work that is larger than a single bug fix.
 
+## Refactoring Follow-Ups
+
+Loose ends found while verifying the [refactoring plan](REFACTORING.md) against
+its Definition of done. The architecture target is reached and verified on
+Windows, but the items below remain.
+
+- **Linux test build is broken (correctness, not cosmetic).** `src/runner/runner_test.go`
+  is a shared (untagged) test file that references Windows-only symbols
+  (`SysProcAttr.HideWindow`, `SysProcAttr.CmdLine`, `windowsShellCommandLine`).
+  The `runtime.GOOS != "windows"` guards are runtime skips and cannot save a file
+  that does not *compile*, so `go test ./...` fails to build on Linux. This
+  contradicts T5.4 ("go test -race clean on both platforms") and the DoD's
+  "green on Windows and Linux." Fix: move the Windows-only tests
+  (`TestShellCommandHidesWindow`, `TestShellCommandUsesWindowsSafeQuoting`, and any
+  peers touching `SysProcAttr` / `windowsShellCommandLine`) into a new
+  `src/runner/runner_windows_test.go` guarded by `//go:build windows`.
+- **File-size guidelines exceeded.** The DoD asks for no `src/ui` file over ~250
+  lines and no single file over ~400:
+  - `src/ui/jobs_view.go` — 415 lines (over both the ~250 UI target and the ~400 cap).
+  - `src/app/operations.go` — 486 lines (over ~400).
+  - `src/app/operations_test.go` (536) and `src/runner/runner_test.go` (421) also
+    exceed 400 if the cap is read to include test files.
+
+  These are soft ("~") limits; revisit when next touching those files rather than
+  splitting purely for line count.
+
 ## Post-Field-Test Cleanup
 
 After real-world use confirms the main workflows, clean up temporary
@@ -24,13 +50,25 @@ Cleanup checklist:
 
 ## Tray Interaction
 
-Improve tray icon interaction after choosing a tray backend path.
+Improve tray icon interaction: click the tray icon to show and focus the main
+window.
 
-- Add double-click on the tray icon to show and focus the main window.
-- Current Fyne 2.5.3 desktop tray API exposes menu and icon setup, but does not
-  expose click or double-click callbacks for the tray icon itself.
-- Revisit when Fyne exposes this callback, or evaluate a small platform-specific
-  tray integration if the behavior becomes important enough.
+- Unblocked by Fyne 2.7.0, which added `desktop.App.SetSystemTrayWindow(window)`.
+  On Windows, macOS, and most Linux it shows the associated window on left-click;
+  any tray menu then moves to right-click. There is still no raw click /
+  double-click callback, so the behavior is single left-click (the conventional
+  tray gesture), not the double-click originally sketched here.
+- The project is currently on Fyne 2.6.3, so this depends on a Fyne 2.6.3 -> 2.7.x
+  upgrade first (minor bump; re-verify the CGO build under MSYS2 UCRT64 and check
+  for 2.7 breaking changes). Track the upgrade as its own task.
+- As part of that upgrade, **re-measure startup time** with the `GOSENTRY_TIMING`
+  method recorded in [PERFORMANCE.md](PERFORMANCE.md). The Fyne 2.5.3 -> 2.6.3 bump
+  added ~290 ms to startup, all inside `w.Show()`; check whether 2.7 recovers any
+  of it or holds steady, and append the result to PERFORMANCE.md.
+- After upgrading, the change in `src/ui/run.go` (configureSystemTray) is small:
+  call `desk.SetSystemTrayWindow(w)` alongside `SetSystemTrayMenu(menu)`. Keep the
+  existing "Show" menu item, which the Fyne docs recommend for less-compliant
+  Linux systems.
 
 ## Delivery And Packaging