feat: add candidate notes schema and migration

Author: zcesur

lib/algora/workspace/schemas/candidate_note.ex

@@ -0,0 +1,32 @@
+defmodule Algora.Workspace.CandidateNote do
+  @moduledoc """
+  Schema for storing candidate notes/highlights.
+  """
+  use Algora.Schema
+
+  alias Algora.Accounts.User
+  alias Algora.Jobs.JobPosting
+  alias Algora.Workspace.CandidateNote
+
+  typed_schema "candidate_notes" do
+    field :notes, {:array, :string}, null: false
+
+    belongs_to :user, User, null: false
+    belongs_to :job, JobPosting
+
+    timestamps()
+  end
+
+  @doc """
+  Changeset for creating or updating candidate notes.
+  """
+  def changeset(%CandidateNote{} = note, attrs) do
+    note
+    |> cast(attrs, [:user_id, :job_id, :notes])
+    |> validate_required([:user_id, :notes])
+    |> generate_id()
+    |> foreign_key_constraint(:user_id)
+    |> foreign_key_constraint(:job_id)
+    |> unique_constraint([:user_id, :job_id])
+  end
+end

priv/repo/migrations/20250603232425_create_candidate_notes.exs

@@ -0,0 +1,17 @@
+defmodule Algora.Repo.Migrations.CreateCandidateNotes do
+  use Ecto.Migration
+
+  def change do
+    create table(:candidate_notes) do
+      add :notes, {:array, :string}, null: false
+      add :user_id, references(:users, on_delete: :delete_all), null: false
+      add :job_id, references(:job_postings, on_delete: :delete_all)
+
+      timestamps()
+    end
+
+    create unique_index(:candidate_notes, [:user_id, :job_id])
+    create index(:candidate_notes, [:user_id])
+    create index(:candidate_notes, [:job_id])
+  end
+end