feat(uat-batch): Group M — universal preview + field-history foundation

M42, M43 from the 2026-05-21 plan.

Shipped:
  M42  FilePreviewDialog now handles seven preview kinds via a single
       previewKindFor() router (mime + filename fallback). Image and
       PDF stay on the existing lightbox + pdf viewer; plain text
       (.txt / .md / .csv / .tsv / .json / .xml / .log / .yaml / .ini
       / .html — text/* and application/json and friends) renders via
       a new <TextPreview> that fetches via the presigned URL and
       caps the body at 1 MB with a "showing first 1 MB" banner.
       Audio / video render through native HTML5 <audio> / <video>
       elements with preload="metadata". Office documents (.docx /
       .xlsx / .pptx / .odt / .ods / .odp + the official mime variants)
       embed via Microsoft's hosted Office viewer (view.officeapps
       .live.com/op/embed.aspx) — presigned download URLs carry the
       token so the embed works without making the file world-public.
       Unknown mime types render a friendly "preview not supported"
       block with a Download CTA instead of an empty pane.
  M43  Field-level override history foundation. Migration 0081 adds
       `interest_field_history` (id, port_id, interest_id?, client_id?,
       field_path, old_value, new_value, source, submission_id?,
       created_at, created_by) with port-scoped indexes on
       (interest_id, created_at desc) and (client_id, created_at desc).
       Drizzle schema + index exports added. supplemental-forms
       applySubmission now collects an `overrides` array as it diffs
       each field against the current entity state and writes them all
       in one batch insert at the end of the transaction, so the
       rep-facing Field history panel can surface every override the
       client made via the form. New
       `GET /api/v1/interests/[id]/field-history` endpoint returns
       the rows newest-first (100-cap). Source on supplemental-info
       submissions is hardcoded to 'supplemental_form'; future
       channels (form-templates, AI extraction) drop new source
       values into the same table.

       The full form-template editor UI (Field-history panels on
       Interest + Client detail, autofill from the bound entity on
       the public form, drag-bind builder in /admin/forms) is queued
       as the next-layer follow-up; the data model + audit trail
       this commit ships are the necessary foundation for it.

Verified: tsc clean, vitest 1454/1454, migration applied.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/db/migrations/0081_interest_field_history.sql

@@ -0,0 +1,36 @@
+-- 2026-05-21: interest_field_history table.
+--
+-- Captures field-level overrides — every time a value on an interest
+-- or its linked client changes via a supplemental-info form (or any
+-- future channel that explicitly records overrides), a row lands here
+-- with the old + new values plus source attribution.
+--
+-- Why a separate table vs piggybacking on `audit_logs`:
+--   - audit_logs is a fire-hose of every CRUD event (~10k rows/day on
+--     a busy port). Filtering for a single field's history is slow.
+--   - This table holds ONLY explicit overrides — much smaller, easier
+--     to surface on the Interest / Client detail "Field history" panel.
+--   - The `source` column lets the UI render meaningful provenance
+--     ("Submitted via supplemental info form on 2026-05-21").
+
+CREATE TABLE IF NOT EXISTS interest_field_history (
+  id text PRIMARY KEY DEFAULT gen_random_uuid()::text,
+  port_id text NOT NULL REFERENCES ports(id),
+  interest_id text REFERENCES interests(id) ON DELETE CASCADE,
+  client_id text REFERENCES clients(id) ON DELETE CASCADE,
+  field_path text NOT NULL,
+  old_value jsonb,
+  new_value jsonb NOT NULL,
+  source text NOT NULL,
+  submission_id text,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  created_by text
+);
+
+CREATE INDEX IF NOT EXISTS idx_ifh_interest_created
+  ON interest_field_history (port_id, interest_id, created_at DESC)
+  WHERE interest_id IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_ifh_client_created
+  ON interest_field_history (port_id, client_id, created_at DESC)
+  WHERE client_id IS NOT NULL;