feat(audit): platform-api audit log + operator UI wired to real events

Phase 1 of the audit work — capture everything we control today, ingest from
external systems (Authentik / OCIS / Stalwart) in a later phase. The mock
OP_AUDIT fixture is gone; both the /audit page and Overview's activity card
now show real events recorded by AuditService.record() in platform-api.

Schema (services/platform-api/src/schemas/audit-event.schema.ts):
  AuditEvent { at, actorType, actorId, actorEmail, actorIp, action, outcome,
    resourceType, resourceId, resourceName, tenantSlug, partnerSlug, source,
    metadata, prevHash, hash }
  Indexes: {at:-1}, {tenantSlug,at:-1}, {actorId,at:-1}, {action,at:-1}.
  prevHash/hash are nullable now; hash-chain tamper evidence is a later phase.

AuditService:
  - record() — best-effort write, swallows errors so the underlying mutation
    that succeeded isn't failed by a downstream log issue. Surfaces failures
    via Logger.
  - list() — filters: since/until/before, action (exact OR prefix match
    via leading-anchor regex), tenantSlug, partnerSlug, actorEmail, outcome,
    free-text q across action/resourceName/actorEmail/tenantSlug, limit
    (default 100, max 500). Cursor pagination via `before`.
  - No UPDATE/DELETE surface — entries are append-only by construction.

AuditController: GET /audit, behind JwtAuthGuard + OperatorGuard. No mutations
exposed; entries written internally by other modules.

X-Forwarded-For threading:
  - apps/operator/server/utils/platform-api.ts forwards the originating
    client IP to platform-api so audit entries carry a real address.
  - services/platform-api/src/auth/client-ip.ts extracts leftmost
    X-Forwarded-For, falls back to socket.remoteAddress.

Instrumented mutations (every one threads actor + IP through):
  Tenants: create, update, softDelete, setStatus(suspend/resume)
  Partners: create, update, terminate
  Flags:   create, update (incl. flag.killed verb when state=off+note=kill-switch),
           remove
  Users:   deactivate

Each controller resolves the User doc via ActorService, extracts IP via
clientIp(req), and passes { userId, email, ip } as AuditActor to the service.
FlagsService's local ActorRef collapses to AuditActor so flag history and the
audit log share one shape.

Operator UI:
  - /api/audit proxy that forwards query params verbatim
  - types/audit.ts
  - pages/audit.vue: real list with quick-pick action chips (All/Tenants/
    Partners/Flags/Users), outcome filter, free-text search, "Load older
    events" cursor pagination
  - pages/index.vue: Overview activity card swaps mock OP_AUDIT for the
    same /api/audit endpoint, rows link into /audit
  - data/fixtures.ts: OP_AUDIT / AuditEntry / AuditTone exports removed

Verified end-to-end: suspended + resumed acme, flipped oci_versioning through
rollout → kill → on, then /audit returned all 5 events with the right action
verbs (tenant.suspended, tenant.resumed, flag.updated, flag.killed,
flag.updated), actor admin@dezky.local, IP 192.168.65.1. Filters (action
prefix + free-text q) narrow correctly.

Out of scope for this commit (each gets its own conversation):
  - Authentik / OCIS / Stalwart ingest adapters (Phase 2)
  - Hash-chain tamper evidence (Phase 3)
  - TTL + cold-storage archival to Hetzner Object Storage (Phase 4)
  - GDPR right-to-erasure tooling

services/platform-api/src/users/users.service.ts

@@ -1,6 +1,7 @@
 import { ConflictException, Injectable, NotFoundException } from '@nestjs/common'
 import { InjectModel } from '@nestjs/mongoose'
 import { Model, Types } from 'mongoose'
+import { AuditService, type AuditActor } from '../audit/audit.service.js'
 import { Tenant, TenantDocument } from '../schemas/tenant.schema.js'
 import { User, UserDocument } from '../schemas/user.schema.js'
 import type { CreateUserDto } from './dto/create-user.dto.js'
@@ -11,6 +12,7 @@ export class UsersService {
   constructor(
     @InjectModel(User.name) private readonly userModel: Model<UserDocument>,
     @InjectModel(Tenant.name) private readonly tenantModel: Model<TenantDocument>,
+    private readonly audit: AuditService,
   ) {}
 
   async create(dto: CreateUserDto): Promise<UserDocument> {
@@ -54,11 +56,20 @@ export class UsersService {
     return user
   }
 
-  async deactivate(subject: string): Promise<void> {
-    const result = await this.userModel
-      .updateOne({ authentikSubjectId: subject }, { active: false })
+  async deactivate(subject: string, actor?: AuditActor): Promise<void> {
+    const user = await this.userModel
+      .findOneAndUpdate({ authentikSubjectId: subject }, { active: false }, { new: true })
       .exec()
-    if (result.matchedCount === 0) throw new NotFoundException(`User ${subject} not found`)
+    if (!user) throw new NotFoundException(`User ${subject} not found`)
+    void this.audit.record(
+      {
+        action: 'user.deactivated',
+        resourceType: 'user',
+        resourceId: String(user._id),
+        resourceName: user.email,
+      },
+      actor,
+    )
   }
 
   // Called on every authenticated request from /users/me. The JWT's groups claim