feat: a dashboard for clients, behind a secret link

Owners and admins turn it on in Configuración → General, pick what it
shows (tickets per status, the sprint under way, release forecasts,
open epics and activity per day) and can renew or drop the link. Whoever
has it sees /share/{token} without an account: only those blocks, no
people nor single tickets but the epics, no links into the app, read
again every minute. A renewed or dropped link says it no longer works.

REST (GET/PUT/DELETE /api/projects/{project}/share and the public
GET /api/shared/dashboards/{token}) and GraphQL (dashboardShare,
shareDashboard, unshareDashboard, sharedDashboard). The token is kept
in dashboard_shares and goes with the project.

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

apps/api/schema.gql

@@ -465,6 +465,16 @@ input CustomFieldValueInput {
   value: String
 }
 
+"""The project's link for clients (owners and admins)"""
+type DashboardShare {
+  blocks: [String!]!
+  createdAt: String!
+  projectId: ID!
+
+  """Secret of the link /share/{token}"""
+  token: String!
+}
+
 """A commit, branch or pull request that mentions the ticket"""
 type DevLink {
   at: String!
@@ -1010,6 +1020,9 @@ type Mutation {
   """Put a ticket in a sprint (null: back to the backlog)"""
   setIssueSprint(issueId: ID!, sprintId: ID): CommandResult!
 
+  """Turn the link on or change its blocks; renew for a new secret"""
+  shareDashboard(input: ShareDashboardInput!): DashboardShare!
+
   """Start a planned sprint (only one under way per project)"""
   startSprint(sprintId: ID!): CommandResult!
 
@@ -1033,6 +1046,9 @@ type Mutation {
   unarchiveProject(projectId: ID!): CommandResult!
   unlinkIssues(input: LinkIssuesInput!): CommandResult!
 
+  """The link stops working"""
+  unshareDashboard(projectId: ID!): Boolean!
+
   """Push off on this device"""
   unsubscribePush(endpoint: String!): Boolean!
 
@@ -1456,6 +1472,9 @@ type Query {
   ): [Activity!]!
   automations(projectId: ID!): [Automation!]!
 
+  """The project's link for clients, if any (owners and admins)"""
+  dashboardShare(projectId: ID!): DashboardShare
+
   """
   A project's epics: top-level tickets that group others, with the progress of those
   """
@@ -1532,6 +1551,9 @@ type Query {
 
   """My views of the project's board, then the shared ones"""
   savedFilters(projectId: ID!): [SavedFilter!]!
+
+  """What a link for clients shows, for anyone with it"""
+  sharedDashboard(token: String!): SharedDashboard
   sprint(id: ID!): Sprint!
 
   """
@@ -1707,6 +1729,50 @@ input SavedFilterCriteriaInput {
   unassigned: Boolean
 }
 
+"""The project's link for clients"""
+input ShareDashboardInput {
+  """Blocks to show: flow, sprint, releases, epics, activity"""
+  blocks: [String!]!
+  projectId: ID!
+
+  """A new secret: the old link stops working"""
+  renew: Boolean
+}
+
+"""
+What a link for clients shows: only the chosen blocks (the others are null)
+"""
+type SharedDashboard {
+  activity: [ActivityDay!]
+  blocks: [String!]!
+  epics: [SharedEpic!]
+  flow: [SharedFlow!]
+  generatedAt: String!
+  projectKey: String!
+  projectName: String!
+  releases: [ReleaseForecast!]
+  sprint: SprintPulse
+}
+
+"""An open epic and how far it got"""
+type SharedEpic {
+  done: Int!
+  dueDate: String
+  key: String!
+  percent: Int!
+  title: String!
+  total: Int!
+}
+
+"""Tickets in one status"""
+type SharedFlow {
+  """A colour name of the project settings"""
+  color: String!
+  count: Int!
+  name: String!
+  status: String!
+}
+
 """A time-boxed iteration: the tickets the team commits to"""
 type Sprint {
   burndown: SprintBurndown!