feat: uuid ids everywhere, pickers for linked tickets, @pi/ui checkboxes

- Postgres: every table has a uuid `id` (gen_random_uuid()); the event
  store keeps its relay order in `seq`, and the lookup tables their
  uniqueness in constraints of their own.
- MongoDB: `_id` is Mongo's ObjectId; `id` is the domain id (the same
  uuid as the aggregate's stream in Postgres), unique, and every query
  goes by it. Production starts from empty databases.
- Web: linking tickets and hanging one from a parent are picked from a
  searchable select (links across projects, parents within the project)
  instead of typing a key; every checkbox is @pi/ui's pi-checkbox.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/infrastructure/src/lib/mongo/read-model.schemas.ts

@@ -15,11 +15,16 @@ import {
   SprintReadModel,
   implicitRank,
 } from '@task-stream/api/tracker/domain';
-import { Schema } from 'mongoose';
+import { Schema, Types } from 'mongoose';
 
 /* Read model (MongoDB): denormalised documents shaped for the GraphQL queries. */
 
-type Doc<T extends { id: string }> = Omit<T, 'id'> & { _id: string };
+/**
+ * Each document keeps the domain id (a uuid, the same one the event store
+ * uses) in `id`, unique; `_id` is Mongo's own ObjectId and means nothing
+ * outside the database.
+ */
+type Doc<T extends { id: string }> = T & { _id?: Types.ObjectId };
 
 export type ProjectDoc = Doc<ProjectReadModel> & { memberIds: string[] };
 /** Links are split: outward ones come from the issue itself, inward ones from other issues' events. */
@@ -34,11 +39,11 @@ export type ActivityDoc = Doc<ActivityReadModel>;
 export type TimelineDoc = Doc<IssueTimelineEntry>;
 export type NotificationDoc = Doc<NotificationReadModel>;
 export type SavedFilterDoc = Doc<SavedFilterReadModel>;
-export type OutgoingWebhookDoc = Omit<OutgoingWebhook, 'id'> & { _id: string };
-export type AutomationDoc = Omit<Automation, 'id'> & { _id: string };
+export type OutgoingWebhookDoc = Doc<OutgoingWebhook>;
+export type AutomationDoc = Doc<Automation>;
 export interface AutomationRunDoc {
   /** `ruleId:eventKey`: a rule runs once per event. */
-  _id: string;
+  id: string;
   at: Date;
 }
 export interface GitRepositoryDoc {
@@ -52,13 +57,15 @@ export interface GitRepositoryDoc {
  * kept: it reads as a repository named "principal" until the list is saved.
  */
 export interface GitIntegrationDoc {
-  _id: string;
+  /** The project's id. */
+  id: string;
   repositories?: GitRepositoryDoc[];
   secret?: string;
   createdAt?: string;
 }
 export interface NotificationSettingsDoc {
-  _id: string;
+  /** The user's id. */
+  id: string;
   email: boolean;
 }
 
@@ -88,11 +95,13 @@ const link = {
   issueId: String,
   issueKey: String,
 };
-const loose = { strict: false, versionKey: false, _id: false } as const;
+const loose = { strict: false, versionKey: false } as const;
+/** The domain id: what every query looks a document up by. */
+const domainId = { type: String, required: true, unique: true };
 
 export const ProjectSchema = new Schema<ProjectDoc>(
   {
-    _id: String,
+    id: domainId,
     key: { type: String, unique: true },
     isPublic: { type: Boolean, index: true },
     memberIds: { type: [String], index: true },
@@ -105,7 +114,7 @@ export const ProjectSchema = new Schema<ProjectDoc>(
 
 export const IssueSchema = new Schema<IssueDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: { type: String, index: true },
     key: { type: String, unique: true },
     status: String,
@@ -149,7 +158,7 @@ IssueSchema.index({ title: 'text', description: 'text', key: 'text' });
 
 export const CommentSchema = new Schema<CommentDoc>(
   {
-    _id: String,
+    id: domainId,
     issueId: { type: String, index: true },
     replyTo: { type: String, index: true },
     author: userRef,
@@ -160,13 +169,13 @@ export const CommentSchema = new Schema<CommentDoc>(
 CommentSchema.index({ issueId: 1, createdAt: 1 });
 
 export const ReleaseSchema = new Schema<ReleaseDoc>(
-  { _id: String, projectId: { type: String, index: true }, version: Number },
+  { id: domainId, projectId: { type: String, index: true }, version: Number },
   { ...loose, collection: 'releases_view' },
 );
 
 export const SprintSchema = new Schema<SprintDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: { type: String, index: true },
     status: String,
     version: Number,
@@ -176,7 +185,7 @@ export const SprintSchema = new Schema<SprintDoc>(
 
 export const ActivitySchema = new Schema<ActivityDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: String,
     issueId: String,
     actor: userRef,
@@ -188,14 +197,14 @@ ActivitySchema.index({ issueId: 1, occurredAt: -1 });
 
 /** Every status and release step of every ticket (statistics). */
 export const TimelineSchema = new Schema<TimelineDoc>(
-  { _id: String, projectId: String, issueId: String, at: String },
+  { id: domainId, projectId: String, issueId: String, at: String },
   { ...loose, collection: 'issue_timeline' },
 );
 TimelineSchema.index({ projectId: 1, at: 1 });
 
 export const NotificationSchema = new Schema<NotificationDoc>(
   {
-    _id: String,
+    id: domainId,
     userId: String,
     readAt: String,
     createdAt: String,
@@ -207,13 +216,13 @@ NotificationSchema.index({ userId: 1, createdAt: -1 });
 NotificationSchema.index({ userId: 1, readAt: 1 });
 
 export const NotificationSettingsSchema = new Schema<NotificationSettingsDoc>(
-  { _id: String, email: Boolean },
+  { id: domainId, email: Boolean },
   { ...loose, collection: 'notification_settings' },
 );
 
 export const SavedFilterSchema = new Schema<SavedFilterDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: String,
     owner: userRef,
     name: String,
@@ -226,13 +235,13 @@ SavedFilterSchema.index({ projectId: 1, 'owner.id': 1 });
 SavedFilterSchema.index({ projectId: 1, shared: 1 });
 
 export const GitIntegrationSchema = new Schema<GitIntegrationDoc>(
-  { _id: String, repositories: [Object], secret: String, createdAt: String },
+  { id: domainId, repositories: [Object], secret: String, createdAt: String },
   { ...loose, collection: 'git_integrations' },
 );
 
 export const OutgoingWebhookSchema = new Schema<OutgoingWebhookDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: { type: String, index: true },
     active: Boolean,
     events: [String],
@@ -244,7 +253,7 @@ export const OutgoingWebhookSchema = new Schema<OutgoingWebhookDoc>(
 
 export const AutomationSchema = new Schema<AutomationDoc>(
   {
-    _id: String,
+    id: domainId,
     projectId: { type: String, index: true },
     active: Boolean,
     createdBy: userRef,
@@ -254,7 +263,7 @@ export const AutomationSchema = new Schema<AutomationDoc>(
 );
 
 export const AutomationRunSchema = new Schema<AutomationRunDoc>(
-  { _id: String, at: Date },
+  { id: domainId, at: Date },
   { ...loose, collection: 'automation_runs' },
 );
 // Redeliveries happen within minutes; a month of memory is plenty.
@@ -277,17 +286,17 @@ export const READ_MODEL_SCHEMAS = [
   { name: ReadModels.SavedFilter, schema: SavedFilterSchema },
 ];
 
-export function fromDoc<T extends { _id: string }>(
-  doc: T,
-): Omit<T, '_id'> & { id: string } {
-  const { _id, ...rest } = doc;
-  return { id: _id, ...rest };
+/** A document as the model it holds: Mongo's own `_id` left out. */
+export function fromDoc<T extends { id: string }>(
+  doc: T & { _id?: unknown },
+): T {
+  const { _id: _ignored, ...rest } = doc;
+  return rest as T;
 }
 
 export function issueFromDoc(doc: IssueDoc): IssueReadModel {
-  const { _id, outwardLinks, inwardLinks, ...rest } = doc;
+  const { _id: _ignored, outwardLinks, inwardLinks, ...rest } = doc;
   return {
-    id: _id,
     ...rest,
     links: [...(outwardLinks ?? []), ...(inwardLinks ?? [])],
     // Tickets projected before attachments existed have none.