fix: Windows reads of lock files, update paths cfg(unix), merge main again (P11c)

spec_vault swept every file under a book, lock files included; on Windows
a held LockFileEx lock is mandatory and the read failed. The locks are
already dedicated files (never data), so the test skips *.lock. Merged
main (P13 step 6, the macOS server.log assert, P11a's AppImage identity):
host.rs keeps main's five-field identity on Unix and size/last-write on
Windows; the update poll and set_program_version are Unix-only.

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

crates/ledger-mcp/src/local.rs

@@ -1121,6 +1121,7 @@ async fn refused_at_door(
             args_digest: None,
             result: Outcome::Refused(code.into()),
             head_after: None,
+            agent: None,
         };
         let written = tokio::task::spawn_blocking(move || access.record(&record)).await;
         if !matches!(written, Ok(Ok(_))) {
@@ -1350,6 +1351,7 @@ async fn upload(
             args_digest: None,
             result: outcome.clone(),
             head_after: None,
+            agent: None,
         };
         let recorded = access.record(&record).is_ok();
         if !recorded && received.is_ok() {
@@ -1524,6 +1526,7 @@ async fn fetch(
                 Err((_, code, _)) => Outcome::Refused((*code).into()),
             },
             head_after: None,
+            agent: None,
         };
         let recorded = access.record(&record).is_ok();
         (found, recorded)