feat(flows): workspace switcher + project-filtered flow list

Mount the shared project switcher (same control as Audit, Approvals
and Runs) in the flow editor's toolbar via the editor's new
toolbarTrailing slot. The list filters by the active project with
'no key = general' display semantics, and new flows are stamped
with the active project's key. Editor pin moved to c4a39a3
(0.25.0 + project separation).

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

CHANGELOG.md

@@ -23,6 +23,16 @@ lockstep.
 - Flow editor pinned at 0.25.0 (store-resolvability split in the
   flow list, three-path analyzer message).
 
+### Added — project separation for flows (0.78.0)
+
+- **Workspace switcher on the Flows page.** The same project
+  selector as Audit/Approvals/Runs now sits in the flow editor's
+  toolbar: it filters the flow list by the active project (flows
+  without a `project:` key count as "general" — display semantics,
+  files are never rewritten) and is the project a new flow gets
+  stamped with. The file keeps winning for runs; the editor's
+  mismatch banner still offers the one-click align.
+
 ### Added — real trust + exposure data (0.77.0)
 
 - **Per-entry install verification.** The hub now reports (since