feat: add bank file import as core, move Enable Banking to extension

Replace PSD2 bank integration as the default with file-based bank
import (CSV/XML), which better suits Swedish sole traders and small
companies. Enable Banking is now an opt-in extension.

- Phase 1: Extract generic transaction ingestion service (ingest.ts)
  with dedup, auto-categorization, and OCR-based invoice matching
- Phase 2: Bank file parser library supporting Nordea, SEB, Swedbank,
  Handelsbanken CSV formats and ISO 20022 camt.053 XML
- Phase 3: Database migration adding import_source, reference columns
  and bank_file_imports tracking table
- Phase 4: Import wizard UI (5-step flow) and API routes for parse/execute
- Phase 5: Move Enable Banking to extensions/enable-banking/ with
  commented-out loader entry for opt-in activation
- Phase 6: 104 new tests (ingestion + all parser formats), fixing
  Nordea detection overlap and camt.053 XML tag collision bugs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

supabase/migrations/20240101000028_bank_file_import_support.sql

@@ -0,0 +1,44 @@
+-- Bank file import support
+-- Adds import_source and reference to transactions,
+-- and a bank_file_imports tracking table
+
+-- Track import origin on transactions
+ALTER TABLE public.transactions ADD COLUMN IF NOT EXISTS import_source text;
+CREATE INDEX IF NOT EXISTS idx_transactions_import_source ON public.transactions(import_source);
+
+-- Store OCR/Bankgiro reference for Swedish payment matching
+ALTER TABLE public.transactions ADD COLUMN IF NOT EXISTS reference text;
+CREATE INDEX IF NOT EXISTS idx_transactions_reference ON public.transactions(reference);
+
+-- Bank file import tracking (prevents duplicate file uploads, provides history)
+CREATE TABLE public.bank_file_imports (
+  id uuid PRIMARY KEY DEFAULT uuid_generate_v4(),
+  user_id uuid REFERENCES auth.users ON DELETE CASCADE NOT NULL,
+  filename text NOT NULL,
+  file_hash text NOT NULL,
+  file_format text NOT NULL,
+  transaction_count integer NOT NULL DEFAULT 0,
+  imported_count integer NOT NULL DEFAULT 0,
+  duplicate_count integer NOT NULL DEFAULT 0,
+  matched_count integer NOT NULL DEFAULT 0,
+  date_from date,
+  date_to date,
+  status text NOT NULL DEFAULT 'pending',
+  error_message text,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  updated_at timestamptz NOT NULL DEFAULT now(),
+  UNIQUE (user_id, file_hash)
+);
+
+ALTER TABLE public.bank_file_imports ENABLE ROW LEVEL SECURITY;
+
+CREATE POLICY "bank_file_imports_select" ON public.bank_file_imports
+  FOR SELECT USING (auth.uid() = user_id);
+CREATE POLICY "bank_file_imports_insert" ON public.bank_file_imports
+  FOR INSERT WITH CHECK (auth.uid() = user_id);
+CREATE POLICY "bank_file_imports_update" ON public.bank_file_imports
+  FOR UPDATE USING (auth.uid() = user_id);
+
+CREATE TRIGGER bank_file_imports_updated_at
+  BEFORE UPDATE ON public.bank_file_imports
+  FOR EACH ROW EXECUTE FUNCTION public.update_updated_at_column();