Add option to filter board cards by labels and assignees (#31999)

Works in both organization and repository project boards

Fixes #21846

Replaces #21963
Replaces #27117
 

![image](https://github.com/user-attachments/assets/1837ace8-3de2-444f-a153-e166bd0da2c0)

**Note** that implementation was made intentionally to work same as in
issue list so that URL can be bookmarked for quick access with
predefined filters in URL

models/issues/issue_project.go

@@ -48,12 +48,12 @@ func (issue *Issue) ProjectColumnID(ctx context.Context) int64 {
 }
 
 // LoadIssuesFromColumn load issues assigned to this column
-func LoadIssuesFromColumn(ctx context.Context, b *project_model.Column) (IssueList, error) {
-	issueList, err := Issues(ctx, &IssuesOptions{
-		ProjectColumnID: b.ID,
-		ProjectID:       b.ProjectID,
-		SortType:        "project-column-sorting",
-	})
+func LoadIssuesFromColumn(ctx context.Context, b *project_model.Column, opts *IssuesOptions) (IssueList, error) {
+	issueList, err := Issues(ctx, opts.Copy(func(o *IssuesOptions) {
+		o.ProjectColumnID = b.ID
+		o.ProjectID = b.ProjectID
+		o.SortType = "project-column-sorting"
+	}))
 	if err != nil {
 		return nil, err
 	}
@@ -78,10 +78,10 @@ func LoadIssuesFromColumn(ctx context.Context, b *project_model.Column) (IssueLi
 }
 
 // LoadIssuesFromColumnList load issues assigned to the columns
-func LoadIssuesFromColumnList(ctx context.Context, bs project_model.ColumnList) (map[int64]IssueList, error) {
+func LoadIssuesFromColumnList(ctx context.Context, bs project_model.ColumnList, opts *IssuesOptions) (map[int64]IssueList, error) {
 	issuesMap := make(map[int64]IssueList, len(bs))
 	for i := range bs {
-		il, err := LoadIssuesFromColumn(ctx, bs[i])
+		il, err := LoadIssuesFromColumn(ctx, bs[i], opts)
 		if err != nil {
 			return nil, err
 		}

models/issues/issue_search.go

@@ -54,6 +54,19 @@ type IssuesOptions struct { //nolint
 	User           *user_model.User           // issues permission scope
 }
 
+// Copy returns a copy of the options.
+// Be careful, it's not a deep copy, so `IssuesOptions.RepoIDs = {...}` is OK while `IssuesOptions.RepoIDs[0] = ...` is not.
+func (o *IssuesOptions) Copy(edit ...func(options *IssuesOptions)) *IssuesOptions {
+	if o == nil {
+		return nil
+	}
+	v := *o
+	for _, e := range edit {
+		e(&v)
+	}
+	return &v
+}
+
 // applySorts sort an issues-related session based on the provided
 // sortType string
 func applySorts(sess *xorm.Session, sortType string, priorityRepoID int64) {

models/organization/org_user.go

@@ -9,7 +9,9 @@ import (
 
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/perm"
+	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/log"
 
 	"xorm.io/builder"
@@ -112,6 +114,49 @@ func IsUserOrgOwner(ctx context.Context, users user_model.UserList, orgID int64)
 	return results
 }
 
+// GetOrgAssignees returns all users that have write access and can be assigned to issues
+// of the any repository in the organization.
+func GetOrgAssignees(ctx context.Context, orgID int64) (_ []*user_model.User, err error) {
+	e := db.GetEngine(ctx)
+	userIDs := make([]int64, 0, 10)
+	if err = e.Table("access").
+		Join("INNER", "repository", "`repository`.id = `access`.repo_id").
+		Where("`repository`.owner_id = ? AND `access`.mode >= ?", orgID, perm.AccessModeWrite).
+		Select("user_id").
+		Find(&userIDs); err != nil {
+		return nil, err
+	}
+
+	additionalUserIDs := make([]int64, 0, 10)
+	if err = e.Table("team_user").
+		Join("INNER", "team_repo", "`team_repo`.team_id = `team_user`.team_id").
+		Join("INNER", "team_unit", "`team_unit`.team_id = `team_user`.team_id").
+		Join("INNER", "repository", "`repository`.id = `team_repo`.repo_id").
+		Where("`repository`.owner_id = ? AND (`team_unit`.access_mode >= ? OR (`team_unit`.access_mode = ? AND `team_unit`.`type` = ?))",
+			orgID, perm.AccessModeWrite, perm.AccessModeRead, unit.TypePullRequests).
+		Distinct("`team_user`.uid").
+		Select("`team_user`.uid").
+		Find(&additionalUserIDs); err != nil {
+		return nil, err
+	}
+
+	uniqueUserIDs := make(container.Set[int64])
+	uniqueUserIDs.AddMultiple(userIDs...)
+	uniqueUserIDs.AddMultiple(additionalUserIDs...)
+
+	users := make([]*user_model.User, 0, len(uniqueUserIDs))
+	if len(userIDs) > 0 {
+		if err = e.In("id", uniqueUserIDs.Values()).
+			Where(builder.Eq{"`user`.is_active": true}).
+			OrderBy(user_model.GetOrderByName()).
+			Find(&users); err != nil {
+			return nil, err
+		}
+	}
+
+	return users, nil
+}
+
 func loadOrganizationOwners(ctx context.Context, users user_model.UserList, orgID int64) (map[int64]*TeamUser, error) {
 	if len(users) == 0 {
 		return nil, nil