Merge pull request #73 from LazyBachelor/LPM-138

LPM-138 Refactor Tui with composable modals and use canvas

Refactors the TUI (dashboard + kanban) to use a shared, composable modal system with canvas-based overlay rendering, while consolidating styling into internal/style and expanding issue interactions (e.g., comments).

Changes:

Introduces a new pkg/tui/modal system (manager/stack + multiple modal types) and overlays modals using Lipgloss compositor layers.
Refactors dashboard/kanban views and input handling to use the modal manager + focus manager instead of per-modal boolean state.
Consolidates TUI styling by moving from pkg/tui/styles to internal/style and updates components to use the new style package; adds a shared footer renderer.

pkg/tui/msgs/msgs.go

@@ -10,35 +10,47 @@ import (
 
 // Msg types used by both dashboard and kanban TUI views.
 type (
+	SwitchToDashboardMsg struct{}
+
+	SwitchToKanbanBoardMsg struct{}
+
+	SelectIssueMsg struct{ IssueID string }
+
 	TitleUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
+
 	DescriptionUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
+
 	StatusUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
+
 	PriorityUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
+
 	TypeUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
+
 	AssigneeUpdatedMsg struct {
 		IssueID string
 		Err     error
 	}
-	SelectIssueMsg struct{ IssueID string }
-	CreatedMsg     struct {
+
+	CreatedMsg struct {
 		Issue *models.Issue
 		Err   error
 	}
+
 	DeletedMsg struct {
 		IssueID       string
 		Err           error
@@ -50,11 +62,14 @@ type (
 		Err     error
 	}
 
-	// SwitchToDashboardMsg signals to switch to the main dashboard view.
-	SwitchToDashboardMsg struct{}
+	ModalCompletedMsg struct {
+		ModalID string
+		Result  interface{}
+	}
 
-	// SwitchToKanbanBoardMsg signals to switch to the kanban board view.
-	SwitchToKanbanBoardMsg struct{}
+	ModalCancelledMsg struct {
+		ModalID string
+	}
 )
 
 // UpdateIssueTitleCmd returns a command that updates an issue's title.