docs(v0.5): describe workspace root vs project subdir in project CLAUDE.md

Rewrites the built-in project CLAUDE.md template with a new Workspace
Structure section that explains the root-vs-subdir split. File
Placement rules refer to the subdirectory. Git section keeps the
single-repo rule and explicitly names the project subdirectory as an
example of where not to init.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/seed/templates.go

@@ -45,28 +45,44 @@ func ClaudeMDProject() string {
 
 This is a ctask project workspace -- a long-lived working environment, not a disposable task.
 
+## Workspace Structure
+
+This is a ctask project workspace. The workspace root contains ctask management
+files. Your project code lives in the project subdirectory.
+
+- Workspace root: ctask metadata, session logs, notes, reference material
+- Project subdirectory: source code, project CLAUDE.md, project configuration
+- ` + "`context/`" + `: reference material and imported specs (workspace level)
+- ` + "`output/`" + `: deliverables and exports (workspace level)
+- ` + "`logs/`" + `: session logs (managed by ctask)
+
+When working on project code, operate inside the project subdirectory.
+Place project-specific CLAUDE.md, documentation, and configuration there.
+
 ## File Placement
 
-- Source code -> ` + "`src/`" + ` or workspace root
-- Documentation -> ` + "`docs/`" + `
-- Deliverables and exports -> ` + "`output/`" + `
-- Reference material -> ` + "`context/`" + `
-- Tests -> ` + "`tests/`" + `
-- Configuration files -> workspace root
+- Source code -> ` + "`src/`" + ` (inside the project subdirectory)
+- Documentation -> ` + "`docs/`" + ` (workspace level for general notes, project subdir for project docs)
+- Deliverables and exports -> ` + "`output/`" + ` (workspace level)
+- Reference material -> ` + "`context/`" + ` (workspace level)
+- Tests -> ` + "`tests/`" + ` (inside the project subdirectory)
+- Configuration files -> inside the project subdirectory
 - Do not place non-code outputs in the workspace root
 
 ## Conventions
 
 - This project uses git. Commit meaningful changes with clear messages.
 - Do not install global packages or modify system files unless asked.
-- Record important assumptions and actions in notes.md.
+- Record important assumptions and actions in notes.md (workspace level).
 - Keep the workspace root clean.
 
 ## Git
 
-This workspace uses a single git repository at the workspace root.
-Do not initialize additional git repositories inside subdirectories.
-All project code, even if nested in a subdirectory, is tracked by the root repo.
+This workspace uses a single git repository initialized at the workspace root.
+The project subdirectory and all its contents are tracked by this root repo.
+Do not initialize additional git repositories inside the project subdirectory
+or any other subdirectory. If you need to check git status or make commits,
+the repo root is the workspace root.
 
 ## Session Handoff
 

internal/seed/templates_test.go

@@ -74,6 +74,21 @@ func TestClaudeMDProjectContainsNestedGitRule(t *testing.T) {
 	}
 }
 
+func TestClaudeMDProjectDescribesWorkspaceStructure(t *testing.T) {
+	body := ClaudeMDProject()
+	for _, must := range []string{
+		"## Workspace Structure",
+		"Workspace root: ctask metadata",
+		"Project subdirectory",
+		"project CLAUDE.md",
+		"operate inside the project subdirectory",
+	} {
+		if !strings.Contains(body, must) {
+			t.Errorf("project CLAUDE.md missing marker %q", must)
+		}
+	}
+}
+
 func TestNotesMDIsASCII(t *testing.T) {
 	content := NotesMD("test title")
 	for i, b := range []byte(content) {