Projects: the snapshot of a project's figures

The project page opens on a snapshot: revenue, direct costs, the
contribution before overhead and its margin of revenue (a segment
margin: revenue less every cost traced to the project, fixed and
variable; B-37 item 7), in the black or red, and for on-spec work the
cost unrecovered if repaid. To date or this fiscal year. By month,
revenue and costs with the net to date in its own strip; costs by
category; the list colors each net by its sign. books.project carries
the same figures, and a parity test runs the viewer and the MCP on the
same books to the cent. Tests honor TMPDIR.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-gui/src/demo.rs

@@ -246,7 +246,13 @@ pub fn build(dir: &Path, today: NaiveDate) -> Result<(), StoreError> {
     let client_class = s.add_project(
         "Client work",
         &ledger_core::ProjectFacts {
-            description: Some("Design work for the studio's clients".into()),
+            // Its invoices can't be tagged to it: an invoice posts one
+            // untagged revenue line (Ledger::create_invoice takes no
+            // class), so only the contractors it pays show here, said so.
+            description: Some(
+                "Design work for the studio's clients. Only its contractors are tagged to it: an invoice can't carry a project yet, so what the clients pay shows on the profit and loss, not here."
+                    .into(),
+            ),
             kind: Some(ledger_core::ProjectKind::Client),
             ..Default::default()
         },