feat(parties): suggestion pipeline from ledger keys and linked documents (#2172)

* feat(parties): phase 1 substrate, one party per counterpart

Adds the identity layer above customers and suppliers, which keep their
tables and every foreign key and gain a nullable party_id.

- parties: company-scoped identity with status (suggested | confirmed),
  kind, alias keys, origin and merged_into. One live party per org number
  and company, enforced by a partial unique index; merged losers leave the
  index so a merge can be undone. This is the unique key the
  duplicate-invoice guard has lacked, since suppliers never had one.
- party_facts: statements with a source, a rank (preferred | normal |
  deprecated) and two time axes, never overwritten.
- party_identities: bankgiro, plusgiro, IBAN and friends per party, with
  seen and paid counts and a known | unverified status.
- party_decisions: every human action on a party as a labelled example.
- normalize_org_number(text): SQL mirror of lib/invariants/org-number.ts
  (strip separators, drop the century on 12 digits, Luhn check, 10 digits).
- ensure_party(): find by org number inside the company, else create.
  Name-only rows never merge at insert time; a name merge is a recorded
  human decision.
- Backfill: one party per existing supplier and customer, merged on org
  number, suppliers first so both roles land on one party.
- Archive contract: the four tables are master data in the full archive.

Observed parties (keys derived from voucher and bank text) are not stored;
they stay computed by the ledger-context RPC. No posted entry is touched.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

* feat(parties): observed parties from voucher text, ledger_key and its mirror

Migrants arrive with vouchers, not bank transactions, so the bank-keyed
ledger context is empty for them. This adds the description-keyed twin.

- public.ledger_key(text): legibility key on top of the frozen
  normalize_counterparty_key mirror: strips AP-register prefixes (levfakt,
  leverantörsfaktura från N, levbet, faktura, kvitto, utgift), the supplier
  number that follows them, and trailing 1-3 digit runs, never "inköp".
  Mirrored by lib/parties/ledger-key.ts; the pair is pinned by a shared
  fixture list in the pg test.
- public.get_observed_parties(company, from_date, limit): posted vouchers
  grouped by ledger_key(description) with occurrences, variants, expense
  and revenue SEK from the lines, first/last seen, median cadence and the
  Laplace-smoothed dominant result account. Excludes storno, opening
  balance, year-end and VAT settlement, and vouchers that carry a bank
  merchant name (those stay with get_ledger_deep_context). SECURITY
  INVOKER, so RLS scopes it. Never stored.
- lib/parties/classify.ts: the deterministic pre-classifier moved out of
  the evaluation script so product and evaluation share one implementation
  (0.965 agreement with the founder labels, party recall 0.99).
- lib/parties/observed.ts: RPC wrapper that classifies each row and
  derives a display rhythm from the cadence.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

* fix(parties): tenant-safe composite foreign keys on every party link

Facts, identities, decisions, customers.party_id, suppliers.party_id and
parties.merged_into now reference parties(id, company_id), so a row can
only point at a party in its own company. ON DELETE SET NULL names
party_id so role rows keep their company_id. Adds a pg-real test that
rejects every cross-company link and checks company_id survives a party
delete.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

* feat(parties): suggestion pipeline from ledger keys and linked documents

Phase 1c of the parties plan. Fills a migrant's register with suggested
parties from what the ledger already knows, never as facts:

- get_ledger_key_evidence(company): hard keys per ledger_key from the
  documents linked to posted vouchers (org number via normalize_org_number,
  VAT, bankgiro, plusgiro, printed name). Documents whose supplier org is
  the company's own are the company's sales invoices and only count in
  self_docs.
- apply_party_suggestions(company, user, items): upserts suggestions.
  Attaches by explicit party_id, org number or an exact alias key; never
  by name. Identities become known at two sightings. Idempotent.
- decide_parties(company, user, ids, kind, note): bulk confirm or dismiss
  with one party_decisions row each.
- parties.suggested_reason: the evidence summary the queue shows per row.
- lib/parties/suggest.ts: buildSuggestions (pure) and
  suggestPartiesForCompany. Keys that mix two org numbers keep neither the
  hard key nor identities; same-core live parties are reported as
  similar_to for a person to decide. coreKey() moves into ledger-key.ts.

55 unit tests and 14 pg-real tests pass locally.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

* fix(parties): decide_parties dismisses suggested parties only

Dismiss is the queue's answer to a suggestion; a confirmed party is never
archived through it. Superagent P2 on #2172.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

* test(parties): type the rpc mock with its args so the ratchet stays clean

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

---------

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

DECISIONS.md

@@ -1503,4 +1503,5 @@ One line per decision: `[YYYY-MM-DD] <decision>: <why>`. Appended by agents and
 [2026-09-02] Bank-sync cooldown is a durable lease column (bank_connections.sync_lease_until, migration 20260902150000) claimed with one conditional UPDATE, not a process-local attempt map: the security scan on PR #2165 showed the map is bypassed by a second serverless instance or a cold start, so two agent calls could each bill Enable Banking. A column add was chosen over reusing extension_data because PostgREST cannot express an atomic conditional upsert there; the nightly cron deliberately ignores the lease.
 [2026-09-02] Grok links carry auth=required like the claude.ai link (#2159), decided from a live test: on the lazy URL Grok's connector dialog listed all 150+ tools and never opened the sign-in, so it reads the 200 probe as an authless server exactly as claude.ai does. The flag lives in one helper (mcpServerUrl / sideDoorServerUrl in lib/onboarding/checklist.ts) so the settings row, the onboarding side door and the deep link cannot drift; ChatGPT stays lazy because its developer mode honours the 401 on the first protected call.
 [2026-09-02] parties children/roles reference parties(id, company_id) with composite FKs, not parties(id): a party UUID from another tenant is rejected by construction instead of relying on each writer to check; ON DELETE SET NULL (party_id) on customers/suppliers because a plain SET NULL would null company_id too (Superagent P2 on #2162)
+[2026-09-02] Party suggestions attach only by explicit party_id, org number or an exact ledger key already in alias_keys; same-core text is reported as similar_to for a person to decide and identities are withheld when a key mixes org numbers: the selection eval measured 9% false merges on trade names shared by distinct legal entities (Fortnox AB / Fortnox Finans), so text never merges
 [2026-09-02] Edited migration 20260902160000 after merge: its backfill failed on prod (ensure_party: name is required; 3 nameless rows) so it was never applied there, the Supabase main branch sat in MIGRATIONS_FAILED and every later migration was blocked behind it. An unapplied file is not a shipped schema; a follow-up migration could not run before it