feat(v0.3): add --project flag, CTASK_TYPE env, project root semantics

ctask new gains --project, which:
  - records type=project on the workspace
  - defaults the category to "projects"
  - applies general + project seed overlays
  - uses CTASK_PROJECT_ROOT when set, with no doubled "projects/"
    path unless the user explicitly passes -c
  - exports CTASK_TYPE=project into the child session

EnvVars now takes a taskType arg and exports CTASK_TYPE. Empty
type defaults to "task" for safety. resume/open also pass
EffectiveType so the env var is correct on resume of a v0.2
workspace.

Git init for project mode is wired in the next commit.

cmd/new.go

@@ -12,8 +12,8 @@ import (
 
 var newCmd = &cobra.Command{
 	Use:          "new [title]",
-	Short:        "Create a new task workspace and launch the agent",
-	Long:         "Create a new task workspace and launch the agent. If title is omitted, generates task-HHMMSS.",
+	Short:        "Create a new task or project workspace and launch the agent",
+	Long:         "Create a new task or project workspace and launch the agent. If title is omitted, generates task-HHMMSS.",
 	Args:         cobra.MaximumNArgs(1),
 	SilenceUsage: true,
 	RunE:         runNew,
@@ -25,10 +25,12 @@ var (
 	newShell     bool
 	newAgent     string
 	newNoLaunch  bool
+	newProject   bool
 )
 
 func init() {
-	newCmd.Flags().StringVarP(&newCategory, "category", "c", "general", "Workspace category subdirectory")
+	newCmd.Flags().StringVarP(&newCategory, "category", "c", "", "Workspace category subdirectory (default: \"general\" for tasks, \"projects\" for projects)")
+	newCmd.Flags().BoolVar(&newProject, "project", false, "Create a project workspace (longer-lived; uses CTASK_PROJECT_ROOT if set, runs git init)")
 	newCmd.Flags().BoolVar(&newContainer, "container", false, "Launch in container sandbox (deferred)")
 	newCmd.Flags().BoolVar(&newShell, "shell", false, "Open interactive shell instead of agent")
 	newCmd.Flags().StringVarP(&newAgent, "agent", "a", "", "Command to exec as the agent")
@@ -42,7 +44,6 @@ func runNew(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
-	root := config.ResolveRoot()
 	agent := newAgent
 	if agent == "" {
 		agent = config.ResolveAgent()
@@ -53,13 +54,45 @@ func runNew(cmd *cobra.Command, args []string) error {
 		title = args[0]
 	}
 
-	ws, err := workspace.Create(workspace.CreateOpts{
-		Root:     root,
-		Title:    title,
-		Category: newCategory,
-		Mode:     "local",
-		Agent:    agent,
-	})
+	// Determine category default and explicit-ness.
+	categoryExplicit := cmd.Flags().Changed("category")
+	category := newCategory
+	if !categoryExplicit {
+		if newProject {
+			category = "projects"
+		} else {
+			category = "general"
+		}
+	}
+
+	// Determine workspace root + skip-category behavior.
+	taskRoot := config.ResolveRoot()
+	root := taskRoot
+	skipCategoryDir := false
+	if newProject {
+		if override := config.ResolveProjectRoot(); override != "" {
+			root = override
+			if !categoryExplicit {
+				skipCategoryDir = true
+			}
+		}
+	}
+
+	opts := workspace.CreateOpts{
+		Root:            root,
+		Title:           title,
+		Category:        category,
+		Mode:            "local",
+		Agent:           agent,
+		IsProject:       newProject,
+		SeedDir:         config.ResolveSeedDir(),
+		SkipCategoryDir: skipCategoryDir,
+	}
+	if newProject {
+		opts.ProjectSeedDir = config.ResolveProjectSeedDir()
+	}
+
+	ws, err := workspace.Create(opts)
 	if err != nil {
 		return err
 	}
@@ -71,7 +104,7 @@ func runNew(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
-	envVars := config.EnvVars(ws.Meta.Slug, ws.Meta.Mode, root, ws.Path, ws.Meta.Category)
+	envVars := config.EnvVars(ws.Meta.Slug, ws.Meta.Mode, root, ws.Path, ws.Meta.Category, workspace.EffectiveType(ws.Meta))
 
 	return session.Run(session.LaunchOpts{
 		WsDir:   ws.Path,