merge: main into P11c (P11b's dock and books homes, the macOS harness root fix)

One conflict, ledger-host commands.rs: main moved the agent-program lookup
into find_agent_in; kept that and carried the Windows parts into it
(.exe/.cmd/.bat, npm's global folder). The harness already used
default_root, so main's fix and ours agree.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

crates/ledger-cli/tests/common/mod.rs

@@ -74,6 +74,10 @@ impl Home {
         }
     }
 
+    /// The root `setup --home` made: the platform's data folder under the
+    /// home (`.local/share` on Linux, `Library/Application Support` on
+    /// macOS), never a Linux path spelled out (the portable macOS job
+    /// found the server refusing a root that was never set up).
     pub fn root(&self) -> PathBuf {
         ledger_store::root::default_root(self.dir.path())
     }