feat(diagram): Personen-Leiste mit Personen-Linse und Belastungsanzeige (D87)

Je @Person eine Pille mit Anteil an der offenen Pfad-Arbeit (D71-Maß),
dazu ein Eintrag für Unzugewiesenes — die Anteile summieren auf 100 %.
Ein Tipp filtert das Diagramm auf die Knoten der Person: alles andere
faltet, ihre Pakete stehen als ▸ n, die Pillen färben petrol. Die Linse
ist rein Ansicht und Sitzungssache — in den Text wird nichts geschrieben,
in geteilten Dokumenten ginge der persönliche Filter sonst an alle.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/examples/werkbaum.werkbaum

@@ -87,6 +87,9 @@
       - [^] #ed.fold.write: Folding writes the mark back into the text (S)  %% one undo step
       - [^] #ed.fold.preset: The fold button cycles through four presets (S)  %% M-and-smaller, off-path, all, none — see D44/D75
     + [?] #ed.textfold: Fold regions in the text editor, next to the line numbers  %% view-only, unrelated to the > marks; not sized yet
+    - [x] #ed.lens: A people bar with a person lens (M)
+      - [x] #ed.lens.fold: One person's nodes, everything else folds (S)  %% view-only, never written into the text
+      - [x] #ed.lens.load: A load bar per person, shares of the open path work (S)  %% the D71 measure
     - [^] #ed.snaps: Earlier states of a document, every ten minutes (S)  %% only when something changed
       - [^] #ed.snaps.manual: Save a state by hand, before a larger change (XS)  %% ten minutes is the wrong beat for that moment
     - [^] #ed.files: Open and save .werkbaum files (S)
@@ -619,6 +622,21 @@
   lines, so this hinges on the parked editor-rebuild question (CodeMirror,
   D76); deliberately not sized yet.
 
+#ed.lens
+  A bar below the diagram, one pill per @person, shown only when the
+  document carries tags at all. Tapping a pill filters the diagram to that
+  person's work; an extra entry shows what is assigned to nobody.
+
+#ed.lens.fold
+  The lens keeps only the ancestor paths to the person's nodes open; their
+  tagged packages stand collapsed. Deliberately view-only: written fold
+  marks would push a personal filter to everyone in a shared document.
+
+#ed.lens.load
+  Each pill carries a bar with the person's share of the open work on the
+  cheapest path — the same measure as the bottleneck warning, shares
+  rather than absolute numbers because the sizes are ordinal.
+
 #ed.snaps
   A safety net against mishaps: the text is put aside every ten minutes, but
   only when it differs from the last one kept, and the last twenty are offered