feat: «Mi día», the few tickets I pick for today

A home panel with the tickets picked for today (10 at most), crossed out
as they get done and counted («1 de 3 terminados»), my open tickets to
add with one click, and what was left unfinished on my last day to carry
over. «☀ Mi día» on a ticket adds it or takes it out. The day is the
person's own (YYYY-MM-DD from the browser); private, no history (Mongo
`my_days`).

API: myDay(day), addToMyDay, removeFromMyDay; GET /api/me/day,
PUT/DELETE /api/me/day/{issue}. MCP: my_day.

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

apps/api/schema.gql

@@ -957,6 +957,9 @@ type Mutation {
   """Add a Pireon user to the project"""
   addProjectMember(input: ProjectMemberInput!): CommandResult!
 
+  """Add tickets to «Mi día» (10 at most)"""
+  addToMyDay(day: String!, issueIds: [ID!]!): Boolean!
+
   """
   Archive the project (owner only): everything stays readable, nothing changes until it is unarchived
   """
@@ -1073,6 +1076,9 @@ type Mutation {
   removeAttachment(attachmentId: ID!, issueId: ID!): CommandResult!
   removeChecklistItem(issueId: ID!, itemId: ID!): CommandResult!
 
+  """Take a ticket out of «Mi día»"""
+  removeFromMyDay(day: String!, issueId: ID!): Boolean!
+
   """Remove a repository; what it linked stays on the tickets"""
   removeGitRepository(projectId: ID!, repositoryId: ID!): Boolean!
   removeProjectMember(projectId: ID!, userId: ID!): CommandResult!
@@ -1210,6 +1216,22 @@ type Mutation {
   writeReleaseNotes(notes: String, releaseId: ID!): CommandResult!
 }
 
+"""«Mi día»: the tickets I picked for today"""
+type MyDay {
+  """YYYY-MM-DD, in my time zone"""
+  day: String!
+
+  """In order, done ones included"""
+  issues: [Issue!]!
+  leftover: MyDayLeftover
+}
+
+"""What was left unfinished on the latest earlier day"""
+type MyDayLeftover {
+  day: String!
+  issues: [Issue!]!
+}
+
 type MyNotifications {
   items: [Notification!]!
 
@@ -1625,6 +1647,14 @@ type Query {
   """My calendar URL, if I made one"""
   myCalendarFeed: CalendarFeed
 
+  """
+  «Mi día»: the tickets I picked for today, and what was left on my last day
+  """
+  myDay(
+    """Today, YYYY-MM-DD in my time zone"""
+    day: String!
+  ): MyDay!
+
   """
   The home page beyond my work: agenda of the week, activity of my projects, the week in numbers, sprints, project cards, suggestions, first steps and who is on what now
   """