Allow multiple projects per issue and pull requests (#36784)

Add ability to add and remove multiple projects per issue
and pull request.

Resolve #12974

---------

Signed-off-by: Icy Avocado <avocado@ovacoda.com>
Co-authored-by: Tyrone Yeh <siryeh@gmail.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: OpenCode (gpt-5.2-codex) <opencode@openai.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

modules/indexer/issues/meilisearch/meilisearch.go

@@ -20,7 +20,7 @@ import (
 )
 
 const (
-	issueIndexerLatestVersion = 4
+	issueIndexerLatestVersion = 5
 
 	// TODO: make this configurable if necessary
 	maxTotalHits = 10000
@@ -71,8 +71,8 @@ func NewIndexer(url, apiKey, indexerName string) *Indexer {
 			"label_ids",
 			"no_label",
 			"milestone_id",
-			"project_id",
-			"project_board_id",
+			"project_ids",
+			"no_project",
 			"poster_id",
 			"assignee_id",
 			"mention_ids",
@@ -182,11 +182,11 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		query.And(inner_meilisearch.NewFilterIn("milestone_id", options.MilestoneIDs...))
 	}
 
-	if options.ProjectID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("project_id", options.ProjectID.Value()))
-	}
-	if options.ProjectColumnID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("project_board_id", options.ProjectColumnID.Value()))
+	if options.NoProjectOnly {
+		query.And(inner_meilisearch.NewFilterEq("no_project", true))
+	} else if len(options.ProjectIDs) > 0 {
+		// FIXME: ISSUE-MULTIPLE-PROJECTS-FILTER: this logic is not right, it should use "AND" but not "OR"
+		query.And(inner_meilisearch.NewFilterIn("project_ids", options.ProjectIDs...))
 	}
 
 	if options.PosterID != "" {