feat: multi-server, list view, tags, activity log + UX polish (v2.2)

[Kofysh]

Overview

Implements the four open roadmap items and a round of UX polish, bumping the app to v2.2.

⚠️ Needs a Windows build to verify. These changes were authored in a Linux environment where WPF cannot be compiled. They were reviewed by inspection and all XAML was validated as well-formed XML, but the real verification is the Windows CI build triggered by this PR.

Roadmap features

• 🌐 Multi-server — connect to several Proxmox clusters at once; VMs/LXC are aggregated across them. The sidebar now lists servers (live machine count + per-server disconnect), and Add server reuses the login window as a dialog. Each MachineData carries its ServerName; power/console/SPICE actions are routed to the matching cluster. State-change tracking and notifications are keyed per server:vmid to avoid collisions across clusters.
• 📋 List view — a DataGrid alternative to the card grid, toggled from the top bar (status, type, VMID, name, status, CPU, RAM, uptime, server, node, tags + inline actions).
• 🏷️ Proxmox tags — shown as chips on each card; click a tag to filter.
• 🕑 Activity log — collapsible side panel recording power actions, state changes, connections and errors (bounded to 200 entries, newest first).

Polish

• Sorting by name / VMID / CPU / RAM / status / uptime
• Active-filter chips (server / node / tag) and an empty-state placeholder
• Keyboard shortcuts: F5 refresh, Ctrl+F focus search, Esc clear search
• StatusMessage surfaced via the snackbar
• Theme and refresh interval now persisted in config and applied at startup
• Bug fix: the card Start button visibility was inverted — BooleanToVisibilityConverter ignores ConverterParameter=inverse, so it now uses InverseBoolToVisibilityConverter

Files

• New: Services/ActivityLogService.cs
• New converters: BoolToGridLengthConverter, CollectionToVisibilityConverter
• Rewritten: ViewModels/MainViewModel.cs, Views/MainWindow.xaml(.cs)
• Touched: ApiClient (Host), MachineData (ServerName), LoginWindow (add-connection mode), App.xaml.cs (apply saved theme), MachineCard, README, version → 2.2.0

Testing

• ✅ All 6 XAML files validated as well-formed XML
• ✅ All command/binding references cross-checked against the view models
• ⬜ Windows compile + runtime smoke test (this PR's CI / manual)

https://claude.ai/code/session_01FhKJ3kR6pgaR4N3sWSfbFX

---

Generated by Claude Code