fix(audit-v2): platform-wide post-merge hardening across 5 domains

Five-domain audit (security, routes, DB, integrations, UI/UX) ran after
the cf37d09 merge. Critical + high-impact items landed here; deferred
medium/low items indexed in docs/audit-final-deferred.md (now organised
into a "Audit-final v2" section).

Security:
- Storage proxy tokens now bind to op (`'get'` vs `'put'`). A long-lived
  download URL minted by `presignDownload` for an emailed brochure can no
  longer be replayed against the proxy PUT to overwrite the original
  storage object. `verifyProxyToken` requires `expectedOp` and rejects
  mismatches; legacy tokens missing `op` fail-closed. Regression tests
  added.
- Markdown email merge values are now markdown-escaped (`[`, `]`, `(`,
  `)`, `*`, `_`, `\`, backticks, braces) before substitution into the
  rep-authored body. A malicious value like `[click here](https://evil)`
  stored in `client.fullName` no longer survives `escapeHtml` to render
  as a real `<a href>` in the outbound email. Phishing-via-merge-field
  closed; regression tests added.
- Middleware now performs an Origin/Referer check on
  POST/PUT/PATCH/DELETE to `/api/v1/**`. Defense-in-depth on top of
  better-auth's SameSite=Lax cookie. Webhooks/public/auth/portal routes
  exempt as they don't carry the session cookie.

Routes:
- Template management routes were calling `withPermission('documents',
  'manage', ...)` — but `documents` doesn't have a `manage` action. The
  registry has `document_templates.manage`. Every non-superadmin was
  getting 403'd on the seven template endpoints. Fixed across the
  /admin/templates surface.
- Custom-fields permission resource is hardcoded to `clients` regardless
  of which entity (yacht/company/etc.) the values belong to. Documented
  as deferred (requires per-entity routes).

DB:
- documentSends: every parent FK (client_id, interest_id, berth_id,
  brochure_id, brochure_version_id) now uses ON DELETE SET NULL so the
  audit trail outlasts hard-deletes. The denormalized columns
  (recipient_email, document_kind, body_markdown, from_address) were
  added precisely for this. Migration 0035.
- Polymorphic discriminators on yachts.current_owner_type and
  invoices.billing_entity_type now have CHECK constraints — typos like
  `'clients'` vs `'client'` were silently inserting unreachable rows
  before. Migration 0036.

Integrations:
- Email attachment resolution (`src/lib/email/index.ts`) was importing
  MinIO directly instead of `getStorageBackend()`. Filesystem-backend
  deployments would have broken every email-with-attachment send. Now
  routes through the pluggable abstraction per CLAUDE.md.
- Documenso DOCUMENT_OPENED webhook filter relaxed: v2 may omit
  `readStatus` or send lowercase, so an event that was the SIGNAL of an
  open was being silently dropped. Now treats any recipient on a
  DOCUMENT_OPENED event as opened.

UI/UX:
- Expense detail used to render `receiptFileIds` as opaque UUID badges —
  reps couldn't view the receipt they uploaded. Now renders an image
  thumbnail (via `/api/v1/files/[id]/preview`) plus a Download link for
  PDFs. Closed the "where's my receipt?" loop in the expense flow.
- Expense detail Edit + Archive buttons now `<PermissionGate>` and the
  archive mutation surfaces success/error toasts instead of silent 403s.
- Brochures admin: setDefault/archive/create mutations now have onError
  toasts (only onSuccess existed before).
- Removed broken bulk-upload link in scan/page (route doesn't exist;
  used a raw `<a>` triggering a full reload to a 404).

Test status: 1168/1168 vitest passing. tsc clean.

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

src/lib/db/migrations/0035_document_sends_preserve_audit_on_parent_delete.sql

@@ -0,0 +1,28 @@
+-- Audit-final v2 fix: document_sends FKs default to NO ACTION which means
+-- a hard-delete of a referenced client/interest/berth/brochure either
+-- silently blocks the parent delete OR (if a future cascade path is added)
+-- nukes the send-out audit row. The audit trail must outlast its source —
+-- recipient_email + document_kind + body_markdown + from_address are
+-- already denormalized onto the row for exactly this purpose.
+--
+-- Switch every parent FK to ON DELETE SET NULL so the audit row keeps a
+-- timestamp + email even when the source row is gone.
+
+ALTER TABLE document_sends
+  DROP CONSTRAINT IF EXISTS document_sends_client_id_clients_id_fk,
+  DROP CONSTRAINT IF EXISTS document_sends_interest_id_interests_id_fk,
+  DROP CONSTRAINT IF EXISTS document_sends_berth_id_berths_id_fk,
+  DROP CONSTRAINT IF EXISTS document_sends_brochure_id_brochures_id_fk,
+  DROP CONSTRAINT IF EXISTS document_sends_brochure_version_id_brochure_versions_id_fk;
+
+ALTER TABLE document_sends
+  ADD CONSTRAINT document_sends_client_id_clients_id_fk
+    FOREIGN KEY (client_id) REFERENCES clients(id) ON DELETE SET NULL,
+  ADD CONSTRAINT document_sends_interest_id_interests_id_fk
+    FOREIGN KEY (interest_id) REFERENCES interests(id) ON DELETE SET NULL,
+  ADD CONSTRAINT document_sends_berth_id_berths_id_fk
+    FOREIGN KEY (berth_id) REFERENCES berths(id) ON DELETE SET NULL,
+  ADD CONSTRAINT document_sends_brochure_id_brochures_id_fk
+    FOREIGN KEY (brochure_id) REFERENCES brochures(id) ON DELETE SET NULL,
+  ADD CONSTRAINT document_sends_brochure_version_id_brochure_versions_id_fk
+    FOREIGN KEY (brochure_version_id) REFERENCES brochure_versions(id) ON DELETE SET NULL;

src/lib/db/migrations/0036_polymorphic_check_constraints.sql

@@ -0,0 +1,13 @@
+-- Audit-final v2 fix: polymorphic discriminator columns are currently free-text
+-- and a typo in service code (e.g. `'clients'` vs `'client'`) inserts silently
+-- and the row becomes unreachable through every read path that uses the
+-- resolver service. Add CHECK constraints on the two most load-bearing
+-- discriminators to surface drift at the DB level.
+
+ALTER TABLE yachts
+  ADD CONSTRAINT yachts_current_owner_type_chk
+    CHECK (current_owner_type IN ('client', 'company'));
+
+ALTER TABLE invoices
+  ADD CONSTRAINT invoices_billing_entity_type_chk
+    CHECK (billing_entity_type IN ('client', 'company'));

src/lib/db/migrations/meta/_journal.json

@@ -246,6 +246,20 @@
       "when": 1778000000000,
       "tag": "0034_normalize_mooring_numbers_broaden",
       "breakpoints": true
+    },
+    {
+      "idx": 35,
+      "version": "7",
+      "when": 1778050000000,
+      "tag": "0035_document_sends_preserve_audit_on_parent_delete",
+      "breakpoints": true
+    },
+    {
+      "idx": 36,
+      "version": "7",
+      "when": 1778100000000,
+      "tag": "0036_polymorphic_check_constraints",
+      "breakpoints": true
     }
   ]
 }

src/lib/db/schema/brochures.ts

@@ -102,17 +102,25 @@ export const documentSends = pgTable(
     portId: text('port_id')
       .notNull()
       .references(() => ports.id),
-    /** Either client_id or interest_id is set (or both). */
-    clientId: text('client_id').references(() => clients.id),
-    interestId: text('interest_id').references(() => interests.id),
+    /**
+     * Either client_id or interest_id is set (or both). All five FKs use
+     * `onDelete: 'set null'` so the audit row survives if the parent
+     * client/interest/berth/brochure is deleted — `recipient_email`,
+     * `document_kind`, `body_markdown`, and `from_address` are denormalized
+     * onto the row precisely so the audit trail outlasts the source.
+     */
+    clientId: text('client_id').references(() => clients.id, { onDelete: 'set null' }),
+    interestId: text('interest_id').references(() => interests.id, { onDelete: 'set null' }),
     recipientEmail: text('recipient_email').notNull(),
     /** 'berth_pdf' | 'brochure' */
     documentKind: text('document_kind').notNull(),
-    berthId: text('berth_id').references(() => berths.id),
+    berthId: text('berth_id').references(() => berths.id, { onDelete: 'set null' }),
     /** Forward FK ref — berth_pdf_versions defined in Phase 6b. Loose-coupled. */
     berthPdfVersionId: text('berth_pdf_version_id'),
-    brochureId: text('brochure_id').references(() => brochures.id),
-    brochureVersionId: text('brochure_version_id').references(() => brochureVersions.id),
+    brochureId: text('brochure_id').references(() => brochures.id, { onDelete: 'set null' }),
+    brochureVersionId: text('brochure_version_id').references(() => brochureVersions.id, {
+      onDelete: 'set null',
+    }),
     /** Exact body used (after merge-field expansion + sanitization). */
     bodyMarkdown: text('body_markdown'),
     sentByUserId: text('sent_by_user_id').notNull(),

src/lib/email/index.ts

@@ -69,7 +69,10 @@ async function resolveAttachments(
   const { files } = await import('@/lib/db/schema/documents');
   const { eq } = await import('drizzle-orm');
   const { ForbiddenError, NotFoundError } = await import('@/lib/errors');
-  const { minioClient } = await import('@/lib/minio');
+  // Pluggable storage backend (s3 OR filesystem). Direct MinIO imports
+  // break the filesystem-mode deployment path documented in CLAUDE.md.
+  const { getStorageBackend } = await import('@/lib/storage');
+  const backend = await getStorageBackend();
 
   return Promise.all(
     refs.map(async (ref) => {
@@ -78,9 +81,9 @@ async function resolveAttachments(
       if (portId && file.portId !== portId) {
         throw new ForbiddenError('File belongs to a different port');
       }
-      const stream = await minioClient.getObject(file.storageBucket, file.storagePath);
+      const stream = await backend.get(file.storagePath);
       const chunks: Buffer[] = [];
-      for await (const chunk of stream) {
+      for await (const chunk of stream as AsyncIterable<Buffer | string>) {
         chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
       }
       return {

src/lib/storage/filesystem.ts

@@ -70,6 +70,17 @@ export function validateStorageKey(key: string): void {
 
 // ─── HMAC token helpers ─────────────────────────────────────────────────────
 
+/**
+ * Token op binding. `'get'` tokens are issued by `presignDownload` and only
+ * accepted by the proxy GET handler. `'put'` tokens are issued by
+ * `presignUpload` and only accepted by the proxy PUT handler. Without this
+ * binding a long-lived 24h download URL emailed to a customer could be
+ * replayed against the PUT handler to overwrite the original storage object
+ * (since both routes share an HMAC and key — the magic-byte check is also
+ * skipped when `c` is unset).
+ */
+export type ProxyTokenOp = 'get' | 'put';
+
 interface ProxyTokenPayload {
   /** Storage key (validated). */
   k: string;
@@ -77,6 +88,11 @@ interface ProxyTokenPayload {
   e: number;
   /** Random nonce so two URLs for the same (key, expiry) differ. */
   n: string;
+  /**
+   * Bound operation. Tokens minted before this field was added (legacy)
+   * fail-closed: the proxy handlers require the field's exact value.
+   */
+  op: ProxyTokenOp;
   /** Optional download filename. */
   f?: string;
   /** Optional content-type override. */
@@ -102,6 +118,12 @@ export function signProxyToken(payload: ProxyTokenPayload, secret: string): stri
 export function verifyProxyToken(
   token: string,
   secret: string,
+  /**
+   * Required: the operation the verifier is allowed to perform. The token
+   * must have been minted with the same `op`. Without this argument an
+   * upload token could be replayed as a download (and vice versa).
+   */
+  expectedOp: ProxyTokenOp,
 ): { ok: true; payload: ProxyTokenPayload } | { ok: false; reason: string } {
   if (typeof token !== 'string' || !token.includes('.')) {
     return { ok: false, reason: 'malformed' };
@@ -138,6 +160,11 @@ export function verifyProxyToken(
   } catch {
     return { ok: false, reason: 'invalid-key' };
   }
+  // Op-binding: tokens minted before this field was added have no `op`
+  // and are now rejected. Fresh tokens must match `expectedOp` exactly.
+  if (payload.op !== expectedOp) {
+    return { ok: false, reason: 'op-mismatch' };
+  }
   return { ok: true, payload };
 }
 
@@ -269,7 +296,7 @@ export class FilesystemBackend implements StorageBackend {
     validateStorageKey(key);
     const expiresAt = Math.floor(Date.now() / 1000) + (opts.expirySeconds ?? 900);
     const token = signProxyToken(
-      { k: key, e: expiresAt, n: randomUUID(), c: opts.contentType },
+      { k: key, e: expiresAt, n: randomUUID(), op: 'put', c: opts.contentType },
       this.hmacSecret,
     );
     return { url: `/api/storage/${token}`, method: 'PUT' };
@@ -280,7 +307,14 @@ export class FilesystemBackend implements StorageBackend {
     const expirySec = opts.expirySeconds ?? 900;
     const expiresAtSec = Math.floor(Date.now() / 1000) + expirySec;
     const token = signProxyToken(
-      { k: key, e: expiresAtSec, n: randomUUID(), f: opts.filename, c: opts.contentType },
+      {
+        k: key,
+        e: expiresAtSec,
+        n: randomUUID(),
+        op: 'get',
+        f: opts.filename,
+        c: opts.contentType,
+      },
       this.hmacSecret,
     );
     // ABSOLUTE URL: send-out emails interpolate this verbatim into the

src/lib/utils/markdown-email.ts

@@ -133,11 +133,41 @@ export function extractTokens(markdown: string): string[] {
   return matches ? Array.from(new Set(matches)) : [];
 }
 
+/**
+ * Markdown-significant characters that need to be neutralized before a merge
+ * value is substituted into the rep-authored body. Without this, a value
+ * like `[click here](https://attacker.tld)` stored on a client/company would
+ * survive `renderEmailBody`'s HTML escape (escapeHtml leaves `[`, `]`, `(`,
+ * `)` intact) and produce a real `<a href>` in the outbound email — a
+ * phishing lure delivered from the legitimate sales account.
+ *
+ * Each char is replaced with its HTML entity. The entity encoding survives
+ * `escapeHtml` (which only re-escapes `&`) and renders as the original
+ * literal character — visually the user still sees their data verbatim,
+ * but the markdown rules (link, emphasis, code) no longer fire on it.
+ */
+const MERGE_VALUE_ESCAPE_MAP: Record<string, string> = {
+  '\\': '&#92;',
+  '`': '&#96;',
+  '*': '&#42;',
+  _: '&#95;',
+  '[': '&#91;',
+  ']': '&#93;',
+  '(': '&#40;',
+  ')': '&#41;',
+  '{': '&#123;',
+  '}': '&#125;',
+};
+
+function escapeMergeValue(value: string): string {
+  return value.replace(/[\\`*_[\](){}]/g, (ch) => MERGE_VALUE_ESCAPE_MAP[ch] ?? ch);
+}
+
 /**
  * Replace `{{token}}` references with values from the supplied map. Tokens
  * not present in the map are left intact so the dry-run reporter can flag
- * them. Values are HTML-escape-safe by virtue of being run BEFORE
- * `renderEmailBody()`; the caller is expected to pass plain strings.
+ * them. Values are markdown-escaped before substitution so a malicious
+ * field cannot inject a link, emphasis, or another `{{token}}` form.
  */
 export function expandMergeTokens(
   markdown: string,
@@ -147,7 +177,7 @@ export function expandMergeTokens(
     const key = `{{${raw}}}`;
     const value = values[key];
     if (value === null || value === undefined || value === '') return full;
-    return String(value);
+    return escapeMergeValue(String(value));
   });
 }