refactor(org): drop legacy adapterLabels / claude_compat fallback; unify connector label resolution

OrgChart and AgentRoster both carried a `claude_compat`-prefix fallback
chained against `adapterLabels[connectorId] ?? connectorId` to paper
over the pre-pi-mono connector id space (claude_local / codex_local /
gemini_local / claude_compat_2..10). The migration to pi-mono's catalog
retired those ids months ago — the fallback is dead code that still
runs `String.prototype.startsWith` on every render and forks the label
resolution into two subtly different shapes in two files.

Replaced with `formatConnectorLabel(connector, fallbackId)` in
lib/formatters.ts, used by both OrgChart and AgentRoster.

Also in this commit (typography polish bundled because touching the
same render paths):

- OrgChart connector label: 9px uppercase tracking-0.08em → 11px
  tracking-tight. The 9px chip was unreadable at default zoom.
- OrgChart zoom controls: `+` / `−` / "Fit" mixed text + character ops
  replaced with Plus / Minus / CornersOut icons (imported from the
  existing icon barrel) + a focus-visible ring for keyboard users.

No rendering changes for the non-cosmetic path (status dots, card
layout, edges). The removed `adapterLabels` map was exported from
orgTreeLayout.ts and had no other importers.

Covers J1 / J3 / J4 / J6 from the team-page audit.

src/renderer/lib/formatters.ts

@@ -46,6 +46,19 @@ export function getAgentInitials(name: string): string {
     .toUpperCase();
 }
 
+/**
+ * Resolve the user-visible label for a connector reference. The org chart
+ * and agent roster share this so there is one definition of "what do I
+ * show for `agent.connectorId`?" — prefer the registered label, fall
+ * back to the raw id when a connector row is missing (e.g. pending sync).
+ */
+export function formatConnectorLabel(
+  connector: { label?: string | null; id?: string | null } | null | undefined,
+  fallbackConnectorId: string,
+): string {
+  return connector?.label || connector?.id || fallbackConnectorId;
+}
+
 export function formatDuration(seconds: number): string {
   if (seconds < 60) return `${seconds}s`;
   const minutes = Math.floor(seconds / 60);