Fix balance sheet: recognize transfers & deposits (unify cash on bank register)

Root cause: accounting.transactions (deposits, transfers, bank payments) never
posted to the GL, and the GL's cash came only from synthesized legs that
hard-coded Undeposited Funds. So the balance sheet ignored transfers (#1) and
showed directly-deposited funds as Undeposited (#2), with banks going negative.

- Post the bank register to the GL: customer receipt -> Dr bank/Cr A/R, vendor
  payment -> Dr A/P/Cr bank, categorized -> Dr/Cr bank+COA, transfer -> Dr dest/
  Cr source, deposit -> Dr bank/Cr Undeposited; payments_received -> Undeposited.
  Retire the synthesized invoice/bill cash legs (acmacc_invpay/billpay) so cash is
  sourced once, from the register. Triggers on transactions/deposits keep it live.
- Fix gl_managed: make it an explicit accounting.companies.gl_auto_post flag
  instead of inferring from null-source journal entries (a single manual journal
  entry had silently disabled all automation for Ashley Manor).

Verified (Ashley Manor): transfer reflected (Cogent +47,127 vs prior -3,521),
deposits land in BOA (Undeposited cleared), R1=0, R7=0, no negative banks.
Imported companies (Bridgewater/Bent Oak) untouched; their residuals stay
surfaced in the Reconciliation report.

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

supabase/migrations/20260602130000_accounting_gl_managed_flag.sql

@@ -0,0 +1,20 @@
+-- Make GL auto-posting an explicit per-company flag instead of inferring it from
+-- the presence of non-acmacc journal entries. The old heuristic
+-- (accounting.gl_managed = "no foreign/imported journal entries") broke the moment
+-- a normal MANUAL journal entry (external_source null) was added to a managed
+-- company — it silently flipped the company to "unmanaged" and disabled all GL
+-- automation. Companies with a large imported GL are flagged off; platform-managed
+-- companies default on.
+alter table accounting.companies add column if not exists gl_auto_post boolean not null default true;
+
+update accounting.companies c set gl_auto_post = false
+where (
+  select count(*) from accounting.journal_entries je
+  where je.company_id = c.id
+    and (je.external_source is null or je.external_source not like 'acmacc_%')
+) > 5;
+
+create or replace function accounting.gl_managed(_company_id uuid)
+returns boolean language sql stable security definer set search_path to 'public','accounting' as $$
+  select coalesce((select gl_auto_post from accounting.companies where id = _company_id), true);
+$$;