Fix idle-state audio handling and tray balloon messaging

AGENTS.md

@@ -0,0 +1,123 @@
+# Codex Rules for EasyBluetoothAudio
+
+## Workflow Orchestration
+
+### Planning
+- Enter plan mode for ANY non-trivial task (3+ steps or architectural decisions)
+- If something goes sideways, STOP and re-plan immediately — don't keep pushing
+- Use plan mode for verification steps, not just building
+- Write detailed specs upfront to reduce ambiguity
+
+### Subagent Strategy
+- Use subagents liberally to keep main context window clean
+- Offload research, exploration, and parallel analysis to subagents
+- For complex problems, throw more compute at it via subagents
+- One task per subagent for focused execution
+
+### Self-Improvement Loop
+- After ANY correction from the user: update `tasks/lessons.md` with the pattern
+- Write rules that prevent the same mistake from recurring
+- Ruthlessly iterate on these lessons until mistake rate drops
+- Review lessons at session start for relevant context
+
+### Verification Before Done
+- Never mark a task complete without proving it works
+- Diff behavior between main and your changes when relevant
+- Ask: "Would a staff engineer approve this?"
+- Run tests, check logs, demonstrate correctness
+
+### Elegance (Balanced)
+- For non-trivial changes: pause and ask "is there a more elegant way?"
+- If a fix feels hacky: implement the elegant solution instead
+- Skip for simple, obvious fixes — don't over-engineer
+
+### Autonomous Bug Fixing
+- When given a bug report: just fix it. Don't ask for hand-holding
+- Point at logs, errors, failing tests — then resolve them
+- Zero context switching required from the user
+
+---
+
+## Task Management
+
+1. **Plan First**: Write plan to `tasks/todo.md` with checkable items
+2. **Verify Plan**: Check in before starting implementation
+3. **Track Progress**: Mark items complete as you go
+4. **Explain Changes**: High-level summary at each step
+5. **Document Results**: Add review section to `tasks/todo.md`
+6. **Capture Lessons**: Update `tasks/lessons.md` after corrections
+
+---
+
+## Core Principles
+
+- **Simplicity First**: Make every change as simple as possible. Impact minimal code.
+- **No Laziness**: Find root causes. No temporary fixes. Senior developer standards.
+- **Minimal Impact**: Changes should only touch what's necessary. Avoid introducing bugs.
+
+---
+
+## WPF MVVM & Clean Code Design Guide
+
+### 1. General Principles
+
+- **Microsoft Guidelines**: Follow official C# and .NET design guidelines (naming, coding style).
+- **Zero Warnings**: Code must compile with zero errors and zero warnings.
+  - Do not suppress warnings unless absolutely necessary (justify via pragma comment).
+  - Fix warnings about missing comments, unused variables, or unreachable code through refactoring.
+- **Commit Rules**:
+  - Never commit broken or non-compiling code.
+  - Commit messages must be meaningful and linked to the respective DevOps item or ticket.
+
+### 2. Refactoring & Clean Code
+
+- **Boy Scout Rule**: Always leave the code cleaner than you found it. Refactor whenever you touch code.
+- **SOLID Principles**: Classes must have a single responsibility; program against interfaces, not concrete implementations.
+- **Coordination**: Changes affecting cross-domain interfaces, database structures, or global configs must be coordinated with the team before implementation.
+
+### 3. Formatting & Comments
+
+- **Curly Brackets — Mandatory**: Every loop or conditional (if/else) must use curly brackets, even for single lines.
+  - Correct: `if (a == b) { DoSomething(); }`
+  - Incorrect: `if (a == b) DoSomething();`
+- **XML Documentation — Strict Rule**:
+  - Every public class, method, variable, property, and enum must have a detailed `/// <summary>`.
+  - For methods: document all `<param>`, `<returns>`, and `<exception>` tags.
+- **Inline Comments**:
+  - Forbidden for obvious code. Code must be self-explanatory through excellent naming.
+  - Only allowed to explain highly complex, business-specific workarounds or algorithms (explain the "Why", not the "What").
+- **File Structure**:
+  - Every class, interface, and enum must reside in its own separate file.
+  - Files exceeding ~300 lines usually indicate an SRP violation and should be split.
+
+### 4. Naming Conventions
+
+- **PascalCase**: Namespaces, Classes, Interfaces (prefix `I`), Methods, Properties, Public Members.
+- **camelCase**: Parameters and local variables.
+- **Private Backing Fields**: Underscore + camelCase (e.g., `_myVariable`). No Hungarian Notation (use `_isActive`, not `_bIsActive`).
+- **Events**: Use `Closing`/`Closed` instead of `BeforeClose`/`AfterClose`. Event handlers follow the `On[EventName]` pattern.
+
+### 5. Interfaces & Dependency Injection
+
+- Interfaces are **mandatory** for: hardware integrations, external API calls, database access, all external services.
+- Access to modules implementing an interface must occur **exclusively** through the interface (IoC).
+- **Forbidden**: Casting an interface to its concrete class to bypass the abstraction (e.g., `(module as MyConcreteService).DoSomethingSecret()`).
+- **DI**: Use `Microsoft.Extensions.DependencyInjection`; inject services via Constructor Injection.
+
+### 6. Architecture & Layer Separation
+
+Strict Clean Architecture layers. Circular dependencies are strictly forbidden.
+
+| Layer | Contents | Dependencies |
+|-------|----------|--------------|
+| **Core / Domain** | Abstract domain models, enums, global interfaces | None |
+| **Application / Services** | Business logic, abstractions, ViewModels | Core only |
+| **Infrastructure / Data** | DB access, external APIs, hardware implementations | Core + Application |
+| **UI / Presentation** | WPF Views and XAML | Application (via ViewModels) |
+
+### 7. WPF & MVVM
+
+- **Separation of Concerns**: Strict separation between GUI and business logic.
+- **DataBindings**: UI communicates with application logic exclusively via DataBindings. GUI controls handle visual states only.
+- **Commands**: User actions (Buttons, Menus, Toolbars) must trigger `ICommand` / `RelayCommand` in the ViewModel.
+- **Code-Behind**: `.xaml.cs` files must remain completely empty except for `InitializeComponent()`. **No business logic in code-behind.**