AGPL source offer, notices and name cleanup

Every build writes the exact tree it was built from, uncommitted work
included, as source.tar.gz next to the app, and names that tree. The sidebar,
user menu, sign-in card and version tooltip link to it.

Coffey Labs' copyright line is added below Stalwart Labs' in every inherited
file changed, and the new files carry Coffey Labs' alone.

The upgrade prompt and its links are gone, the edition tooltip is neutral,
storage keys and the package description are INBUXA's own, and the README
states the lineage once, in the fine print.

src/components/layout/Sidebar.tsx

@@ -1,5 +1,6 @@
 /*
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
  */
@@ -11,6 +12,7 @@ const { ChevronDown, Lock } = LucideIcons;
 import { cn } from '@/lib/utils';
 import { Button } from '@/components/ui/button';
 import { EnterpriseUpsell } from '@/components/common/EnterpriseUpsell';
+import { SourceLink } from '@/components/common/SourceLink';
 import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';
 import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
 import { useUIStore } from '@/stores/uiStore';
@@ -399,6 +401,11 @@ export function Sidebar() {
           </TooltipProvider>
         )}
 
+        {/* INBUXA: the AGPL's offer, always on screen: the exact source of this version. */}
+        <div className="border-t px-3 py-2 text-center text-[11px] leading-tight text-muted-foreground">
+          <SourceLink className="underline-offset-2 hover:text-foreground hover:underline" />
+        </div>
+
         <EnterpriseUpsell open={upsellOpen} onClose={() => setUpsellOpen(false)} />
       </aside>
     </>