Grow a real OKR company: officers, departments, ranks - and a stable chart

Researched how OKR-run companies cascade (company objective -> C-suite
officers per function -> department objectives -> individual key
results) and encoded that shape into how the CEO builds the org.

- hire_agent gains seniority (director/lead/staff; c_suite stays
  reserved for the CEO's privileges) and a business-card title, so the
  CEO hires a CTO/CFO/CMO as directors instead of a flat pool of ICs
- CEO persona + goal kickoff now direct the OKR cascade: hire 2-4
  officers, hand each a department objective, let them build teams;
  department heads get their own doctrine (hire leads/staff, cascade
  key results as tasks, report up)
- Migration 050 adds Finance and Sales to every org's canonical
  departments (backfilled for existing DBs) so a real C-suite has
  somewhere to hire
- Org chart viewport is a fixed-height scroll region: zooming rescales
  the diagram inside it instead of resizing the card
- Unit test drives a live three-level chain: CEO -> CTO (director) ->
  Engineering Manager (lead) -> staff, with rank/title persisted

src/renderer/src/styles.css

@@ -585,7 +585,7 @@ a { color: inherit; }
   font-variant-numeric: tabular-nums;
 }
 .org-zoom-label:hover { background: var(--hover); color: var(--text-1); }
-.org-scroll { overflow: auto; max-height: 62vh; }
+.org-scroll { overflow: auto; height: 56vh; min-height: 320px; }
 .org-sizer { position: relative; margin: 20px auto 4px; }
 .org-canvas { position: absolute; top: 0; left: 0; }
 .org-node-card {