fix(plan): readable audit descriptions, project labels, dashboard invalidation, view-only & sticky-column UI

Work-plan fixes from this session:
- Czech audit descriptions for plan entries/overrides (was empty '-')
- server-embedded project label on grid cells (was '-' past the 100-project cap)
- dashboard activity + audit-log cache invalidation on plan mutations
- read-only cells: no '+' on empty, keep hover on cells with a record
- view modal: Czech category + formatted dates
- sticky date column made opaque (no bleed-through on horizontal scroll)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/routes/admin/plan.ts

@@ -156,7 +156,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityType: "work_plan_entry",
         entityId: (result.data as any).id,
         newValues: result.data,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, result.data, 201, "Plán vytvořen");
     },
@@ -187,7 +187,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityId: id,
         oldValues: (result.oldData as any) ?? undefined,
         newValues: result.data as Record<string, unknown>,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, result.data, 200, "Plán aktualizován");
     },
@@ -210,7 +210,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityType: "work_plan_entry",
         entityId: id,
         oldValues: (result.oldData as any) ?? undefined,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, { ok: true }, 200, "Plán smazán");
     },
@@ -240,7 +240,7 @@ export default async function planRoutes(app: FastifyInstance) {
           entityType: "work_plan_override",
           entityId: (result.replacedData as any).id,
           oldValues: result.replacedData as Record<string, unknown>,
-          description: "auto-soft-delete before replace",
+          description: result.replacedDescription,
         });
       }
       await logAudit({
@@ -250,7 +250,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityType: "work_plan_override",
         entityId: (result.data as any).id,
         newValues: result.data,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, result.data, 201, "Přepsání dne vytvořeno");
     },
@@ -281,7 +281,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityId: id,
         oldValues: (result.oldData as any) ?? undefined,
         newValues: result.data,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, result.data, 200, "Přepsání aktualizováno");
     },
@@ -304,7 +304,7 @@ export default async function planRoutes(app: FastifyInstance) {
         entityType: "work_plan_override",
         entityId: id,
         oldValues: (result.oldData as any) ?? undefined,
-        description: force ? "force-edit past date" : undefined,
+        description: result.description,
       });
       return success(reply, { ok: true }, 200, "Přepsání smazáno");
     },