Retire the Pipeline page's "+ New Opportunity" button (v0.1.0:88)

Opportunities are now born only from a fundraising-grid investor row
("+ Pipeline"), which matches how the team works — they live in the grid,
not on the board. The old "+ New Opportunity" button created a deal by
picking a contact, a path that contradicts the grid-is-canonical model and
the contact-vs-investor framing.

Remove the button, its create-by-contact modal, the now-dead handler/state,
and the Pipeline page's unused /api/contacts fetch. Replace the button with a
muted "Add deals from the Fundraising Grid" hint. The board is now a view +
stage-management surface. Frontend-only; no backend or schema change.

Render-smoke green.

start9/0.4/startos/versions/v0.1.0.88.ts

@@ -0,0 +1,20 @@
+import { VersionInfo } from '@start9labs/start-sdk'
+
+// Frontend-only follow-up to Adopt the Pipeline (v0.1.0:87). Retires the Pipeline page's
+// "+ New Opportunity" button and its create-by-contact modal: an opportunity is now born
+// ONLY from a fundraising-grid investor row ("+ Pipeline"), which matches how the team
+// actually works (they live in the grid, not on the board). The board becomes a view +
+// stage-management surface. The button is replaced with a muted "Add deals from the
+// Fundraising Grid" hint; the dead handler/state and the page's unused /api/contacts fetch
+// are removed. No schema change, no backend change.
+export const v_0_1_0_88 = VersionInfo.of({
+  version: '0.1.0:88',
+  releaseNotes: {
+    en_US: [
+      'Pipeline board: removed the "+ New Opportunity" button — deals are now added only',
+      'from an investor row in the Fundraising Grid ("+ Pipeline"), keeping the grid the',
+      'single place you create work. No data changes.',
+    ].join(' '),
+  },
+  migrations: { up: async () => {}, down: async () => {} },
+})