feat(pitch-deck): full pitch versioning with git-style history (#4)

Full pitch versioning: 12 data tables versioned as JSONB snapshots,
git-style parent chain (draft→commit→fork), per-investor assignment,
side-by-side diff engine, version-aware /api/data + /api/financial-model.

Bug fixes: FM editor [object Object] for JSONB arrays, admin scroll.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pitch-deck/lib/version-helpers.ts

@@ -0,0 +1,76 @@
+import pool from './db'
+
+/**
+ * The 12 data tables tracked per version.
+ * Each maps to a pitch_version_data.table_name value.
+ */
+export const VERSION_TABLES = [
+  'company', 'team', 'financials', 'market', 'competitors',
+  'features', 'milestones', 'metrics', 'funding', 'products',
+  'fm_scenarios', 'fm_assumptions',
+] as const
+
+export type VersionTableName = typeof VERSION_TABLES[number]
+
+/** Maps version table names to the actual DB table + ORDER BY */
+const TABLE_QUERIES: Record<VersionTableName, string> = {
+  company:        'SELECT * FROM pitch_company LIMIT 1',
+  team:           'SELECT * FROM pitch_team ORDER BY sort_order',
+  financials:     'SELECT * FROM pitch_financials ORDER BY year',
+  market:         'SELECT * FROM pitch_market ORDER BY id',
+  competitors:    'SELECT * FROM pitch_competitors ORDER BY id',
+  features:       'SELECT * FROM pitch_features ORDER BY sort_order',
+  milestones:     'SELECT * FROM pitch_milestones ORDER BY sort_order',
+  metrics:        'SELECT * FROM pitch_metrics ORDER BY id',
+  funding:        'SELECT * FROM pitch_funding LIMIT 1',
+  products:       'SELECT * FROM pitch_products ORDER BY sort_order',
+  fm_scenarios:   'SELECT * FROM pitch_fm_scenarios ORDER BY is_default DESC, name',
+  fm_assumptions: 'SELECT * FROM pitch_fm_assumptions ORDER BY sort_order',
+}
+
+/**
+ * Snapshot all base tables into pitch_version_data for a given version.
+ */
+export async function snapshotBaseTables(versionId: string, adminId: string | null): Promise<void> {
+  const client = await pool.connect()
+  try {
+    for (const tableName of VERSION_TABLES) {
+      const { rows } = await client.query(TABLE_QUERIES[tableName])
+      await client.query(
+        `INSERT INTO pitch_version_data (version_id, table_name, data, updated_by)
+         VALUES ($1, $2, $3, $4)
+         ON CONFLICT (version_id, table_name) DO UPDATE SET data = $3, updated_at = NOW(), updated_by = $4`,
+        [versionId, tableName, JSON.stringify(rows), adminId],
+      )
+    }
+  } finally {
+    client.release()
+  }
+}
+
+/**
+ * Copy all version data from one version to another.
+ */
+export async function copyVersionData(fromVersionId: string, toVersionId: string, adminId: string | null): Promise<void> {
+  await pool.query(
+    `INSERT INTO pitch_version_data (version_id, table_name, data, updated_by)
+     SELECT $1, table_name, data, $3
+     FROM pitch_version_data WHERE version_id = $2`,
+    [toVersionId, fromVersionId, adminId],
+  )
+}
+
+/**
+ * Load all version data as a map of table_name → JSONB rows.
+ */
+export async function loadVersionData(versionId: string): Promise<Record<string, unknown[]>> {
+  const { rows } = await pool.query(
+    `SELECT table_name, data FROM pitch_version_data WHERE version_id = $1`,
+    [versionId],
+  )
+  const result: Record<string, unknown[]> = {}
+  for (const row of rows) {
+    result[row.table_name] = typeof row.data === 'string' ? JSON.parse(row.data) : row.data
+  }
+  return result
+}