feat(assets): atomic asset disposal workflow (avyttring, utrangering, verksamhetsoverlatelse) (#1391)

* feat(assets): atomic asset disposal workflow (avyttring, utrangering, verksamhetsoverlatelse)

Disposal books depreciation to the disposal date, clears cost and
accumulated depreciation, books gain (3973) or loss (7973), applies
output VAT on third-party sales, honors the ML 5 kap. 38 §
verksamhetsoverlatelse exemption, and recalculates ML 15 kap. jamkning
server-side from tax years and original input VAT. The voucher, the
disposal-date depreciation schedule and the immutable register state
commit in one dedicated commit_asset_disposal RPC transaction that
delegates voucher numbering to commit_journal_entry.

Fixes #325

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(assets): harden disposal per review and pg-real findings

- commit_asset_disposal now uses the NULL-safe caller_is_company_member()
  guard (tenant-guard ratchet) and passes the allowed 'user_accept'
  commit_method instead of the unlisted 'asset_disposal' value
- disposal metadata invariants validated in the RPC (non-negative
  proceeds/VAT, VAT requires a treatment, VAT <= gross, scrap carries no
  proceeds) since the RPC is independently callable
- new FK and CHECK constraints added NOT VALID + VALIDATE CONSTRAINT so
  the migration never blocks writes on the hot journal_entries table
- disposeAsset paginates fiscal periods and depreciation schedules with
  fetchAllRows; jamkning_remaining_years keeps a valid 0 (?? not ||)
- engine imports shared AssetDisposalType/AssetJamkningDirection/
  VatTreatment unions; post-commit reload retries once and logs before
  surfacing, so a transient read cannot masquerade as a failed disposal
- dispose page parses Swedish-formatted amounts (125 000,50) and blocks
  submission on unparseable proceeds
- assets pg tests write disposal attributes in the disposal transition
  itself and gain a regression test that the register is frozen after

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

tests/pg/assets.pg.test.ts

@@ -396,15 +396,17 @@ describe('RLS: cross-company isolation', () => {
 // can't loosen them without us noticing.
 describe('assets: disposal VAT + jämkning constraints', () => {
   it('accepts a disposed_vat_treatment from the allowed enum', async () => {
+    // Disposal attributes are written in the same UPDATE that transitions the
+    // asset to disposed: once disposed_at is set, the post-disposal
+    // immutability trigger (20260803226000) freezes them.
     const assetId = await insertAsset({
       userId: companyA.userId,
       companyId: companyA.companyId,
-      disposedAt: '2025-12-31',
-      disposedProceeds: 100_000,
     })
     await getPool().query(
       `UPDATE public.assets
-         SET disposed_proceeds_vat = 20000, disposed_vat_treatment = 'standard_25'
+         SET disposed_at = '2025-12-31', disposed_proceeds = 100000,
+             disposed_proceeds_vat = 20000, disposed_vat_treatment = 'standard_25'
        WHERE id = $1`,
       [assetId],
     )
@@ -420,12 +422,13 @@ describe('assets: disposal VAT + jämkning constraints', () => {
     const assetId = await insertAsset({
       userId: companyA.userId,
       companyId: companyA.companyId,
-      disposedAt: '2025-12-31',
-      disposedProceeds: 100_000,
     })
     await expect(
       getPool().query(
-        `UPDATE public.assets SET disposed_vat_treatment = 'reduced_999' WHERE id = $1`,
+        `UPDATE public.assets
+           SET disposed_at = '2025-12-31', disposed_proceeds = 100000,
+               disposed_vat_treatment = 'reduced_999'
+         WHERE id = $1`,
         [assetId],
       ),
     ).rejects.toThrow(/check/i)
@@ -435,20 +438,36 @@ describe('assets: disposal VAT + jämkning constraints', () => {
     const assetId = await insertAsset({
       userId: companyA.userId,
       companyId: companyA.companyId,
-      disposedAt: '2025-12-31',
-      disposedProceeds: 100_000,
     })
     // Treatment NULL + VAT > 0 must violate the consistency CHECK.
     await expect(
       getPool().query(
         `UPDATE public.assets
-           SET disposed_proceeds_vat = 20000, disposed_vat_treatment = NULL
+           SET disposed_at = '2025-12-31', disposed_proceeds = 100000,
+               disposed_proceeds_vat = 20000, disposed_vat_treatment = NULL
          WHERE id = $1`,
         [assetId],
       ),
     ).rejects.toThrow(/check|consistency/i)
   })
 
+  it('freezes disposal attributes once the asset is disposed', async () => {
+    const assetId = await insertAsset({
+      userId: companyA.userId,
+      companyId: companyA.companyId,
+      disposedAt: '2025-12-31',
+      disposedProceeds: 100_000,
+    })
+    await expect(
+      getPool().query(
+        `UPDATE public.assets
+           SET disposed_proceeds_vat = 20000, disposed_vat_treatment = 'standard_25'
+         WHERE id = $1`,
+        [assetId],
+      ),
+    ).rejects.toThrow(/disposed asset/i)
+  })
+
   it('accepts zero VAT with null treatment (legacy / non-VAT disposal)', async () => {
     const assetId = await insertAsset({
       userId: companyA.userId,
@@ -469,12 +488,12 @@ describe('assets: disposal VAT + jämkning constraints', () => {
     const assetId = await insertAsset({
       userId: companyA.userId,
       companyId: companyA.companyId,
-      disposedAt: '2025-12-31',
-      disposedProceeds: 60_000,
     })
     await getPool().query(
       `UPDATE public.assets
-         SET jamkning_amount = 8000,
+         SET disposed_at = '2025-12-31',
+             disposed_proceeds = 60000,
+             jamkning_amount = 8000,
              jamkning_remaining_months = 24,
              jamkning_total_months = 60,
              jamkning_original_input_vat = 20000