chore: update `AGENTS.md`, mention `x/ansi` package

AGENTS.md

@@ -7,17 +7,18 @@
 - **Update Golden Files**: `go test ./... -update` (regenerates .golden files when test output changes)
   - Update specific package: `go test ./internal/tui/components/core -update` (in this case, we're updating "core")
 - **Lint**: `task lint:fix`
-- **Format**: `task fmt` (gofumpt -w .)
+- **Format**: `task fmt` (`gofumpt -w .`)
+- **Modernize**: `task modernize` (runs `modernize` which make code simplifications)
 - **Dev**: `task dev` (runs with profiling enabled)
 
 ## Code Style Guidelines
 
-- **Imports**: Use goimports formatting, group stdlib, external, internal packages
+- **Imports**: Use `goimports` formatting, group stdlib, external, internal packages
 - **Formatting**: Use gofumpt (stricter than gofmt), enabled in golangci-lint
 - **Naming**: Standard Go conventions - PascalCase for exported, camelCase for unexported
 - **Types**: Prefer explicit types, use type aliases for clarity (e.g., `type AgentName string`)
 - **Error handling**: Return errors explicitly, use `fmt.Errorf` for wrapping
-- **Context**: Always pass context.Context as first parameter for operations
+- **Context**: Always pass `context.Context` as first parameter for operations
 - **Interfaces**: Define interfaces in consuming packages, keep them small and focused
 - **Structs**: Use struct embedding for composition, group related fields
 - **Constants**: Use typed constants with iota for enums, group in const blocks

internal/ui/AGENTS.md

@@ -1,15 +1,25 @@
 # UI Development Instructions
 
 ## General Guidelines
+
 - Never use commands to send messages when you can directly mutate children or state.
 - Keep things simple; do not overcomplicate.
 - Create files if needed to separate logic; do not nest models.
 - Never do IO or expensive work in `Update`; always use a `tea.Cmd`.
 - Never change the model state inside of a command use messages and than update the state in the main loop
+- Use the `github.com/charmbracelet/x/ansi` package for any string manipulation
+  that might involves ANSI codes. Do not manipulate ANSI strings at byte level!
+  Some useful functions:
+  * `ansi.Cut`
+  * `ansi.StringWidth`
+  * `ansi.Strip`
+  * `ansi.Truncate`
+
 
 ## Architecture
 
 ### Main Model (`model/ui.go`)
+
 Keep most of the logic and state in the main model. This is where:
 - Message routing happens
 - Focus and UI state is managed
@@ -17,35 +27,42 @@ Keep most of the logic and state in the main model. This is where:
 - Dialogs are orchestrated
 
 ### Components Should Be Dumb
+
 Components should not handle bubbletea messages directly. Instead:
 - Expose methods for state changes
 - Return `tea.Cmd` from methods when side effects are needed
 - Handle their own rendering via `Render(width int) string`
 
 ### Chat Logic (`model/chat.go`)
+
 Most chat-related logic belongs here. Individual chat items in `chat/` should be simple renderers that cache their output and invalidate when data changes (see `cachedMessageItem` in `chat/messages.go`).
 
 ## Key Patterns
 
 ### Composition Over Inheritance
+
 Use struct embedding for shared behaviors. See `chat/messages.go` for examples of reusable embedded structs for highlighting, caching, and focus.
 
 ### Interfaces
+
 - List item interfaces are in `list/item.go`
 - Chat message interfaces are in `chat/messages.go`
 - Dialog interface is in `dialog/dialog.go`
 
 ### Styling
+
 - All styles are defined in `styles/styles.go`
 - Access styles via `*common.Common` passed to components
 - Use semantic color fields rather than hardcoded colors
 
 ### Dialogs
+
 - Implement the dialog interface in `dialog/dialog.go`
 - Return message types from `Update()` to signal actions to the main model
 - Use the overlay system for managing dialog lifecycle
 
 ## File Organization
+
 - `model/` - Main UI model and major components (chat, sidebar, etc.)
 - `chat/` - Chat message item types and renderers
 - `dialog/` - Dialog implementations
@@ -56,6 +73,7 @@ Use struct embedding for shared behaviors. See `chat/messages.go` for examples o
 - `logo/` - Logo rendering
 
 ## Common Gotchas
+
 - Always account for padding/borders in width calculations
 - Use `tea.Batch()` when returning multiple commands
 - Pass `*common.Common` to components that need styles or app access