Opening balances post to GL; unify all reports on the general ledger

- Opening balances now post a single "Opening Balances" journal entry to the GL
  (migration applied to prod), scoped to managed companies (imported-GL
  associations already carry theirs). Triggers on opening_balances /
  opening_balances_setup keep it in sync; Ashley Manor backfilled.
- Balance Sheet: read balances from the GL only (drop the separate opening add,
  which also double-counted imported companies).
- Trial Balance: compute balances from journal_entry_lines as of the report date
  (was accounts.balance).
- General Ledger report: read from journal_entry_lines (was transactions); opening
  rolls in from the GL.

All four reports now share one source. Verified Ashley Manor TB balances
(debits = credits = $90,073.23) with opening cash (BOA +$47,304.31) flowing through.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

supabase/migrations/20260601160000_accounting_opening_balances_to_gl.sql

@@ -0,0 +1,54 @@
+-- Post opening balances (accounting.opening_balances) to the general ledger as a
+-- single "Opening Balances" journal entry, so they flow into every GL-based
+-- report (Trial Balance, General Ledger, P&L, Balance Sheet) from one source.
+--
+-- Scoped by accounting.gl_managed(): only companies whose GL we generate (no
+-- imported/foreign journal entries). Imported-GL companies (e.g. Bridgewater,
+-- Bent Oak) already carry their opening balances inside the imported GL, so we
+-- must NOT post theirs again. Keyed external_source='acmacc_opening',
+-- external_id=company_id (one entry per company) — idempotent.
+
+create or replace function accounting.post_opening_balance_gl(_company_id uuid) returns void
+language plpgsql security definer set search_path to 'public','accounting' as $$
+declare _dt date; _je uuid; _has boolean;
+begin
+  perform accounting._gl_clear(_company_id, 'acmacc_opening', _company_id::text);
+  if not accounting.gl_managed(_company_id) then return; end if;
+
+  select exists (
+    select 1 from accounting.opening_balances
+    where company_id=_company_id and (coalesce(debit,0) <> 0 or coalesce(credit,0) <> 0)
+  ) into _has;
+  if not _has then return; end if;
+
+  select as_of_date into _dt from accounting.opening_balances_setup where company_id=_company_id;
+  _dt := coalesce(_dt, date_trunc('year', now())::date);
+
+  insert into accounting.journal_entries (company_id, date, description, reference, external_source, external_id)
+  values (_company_id, _dt, 'Opening Balances', 'OPENING', 'acmacc_opening', _company_id::text)
+  returning id into _je;
+
+  insert into accounting.journal_entry_lines (journal_entry_id, account_id, debit, credit, description)
+  select _je, ob.account_id, coalesce(ob.debit,0), coalesce(ob.credit,0), 'Opening balance'
+  from accounting.opening_balances ob
+  where ob.company_id=_company_id and (coalesce(ob.debit,0) <> 0 or coalesce(ob.credit,0) <> 0);
+end$$;
+
+create or replace function accounting.tg_opening_balance_gl() returns trigger
+language plpgsql security definer set search_path to 'public','accounting' as $$
+begin
+  begin
+    perform accounting.post_opening_balance_gl(coalesce(new.company_id, old.company_id));
+  exception when others then
+    raise warning 'accounting: opening-balance GL post failed for %: %', coalesce(new.company_id, old.company_id), sqlerrm;
+  end;
+  return coalesce(new, old);
+end$$;
+
+drop trigger if exists trg_acct_opening_gl on accounting.opening_balances;
+create trigger trg_acct_opening_gl after insert or update or delete on accounting.opening_balances
+  for each row execute function accounting.tg_opening_balance_gl();
+
+drop trigger if exists trg_acct_opening_setup_gl on accounting.opening_balances_setup;
+create trigger trg_acct_opening_setup_gl after insert or update on accounting.opening_balances_setup
+  for each row execute function accounting.tg_opening_balance_gl();