feat: add unaccent support for accent-insensitive search (#1402)

- Add PostgreSQL unaccent and pg_trgm extensions
- Create immutable f_unaccent wrapper function for performance
- Update all search queries to use f_unaccent for accent-insensitive matching
- Add 1MB limit to tsvector content to prevent errors on large documents
- Update full-text search trigger to use f_unaccent
- Fix MultiSelect client-side filtering to show server results properly

apps/server/src/database/migrations/20250723T125234-add-unaccent-pg_trm-update-tsvector.ts

@@ -0,0 +1,50 @@
+import { type Kysely, sql } from 'kysely';
+
+export async function up(db: Kysely<any>): Promise<void> {
+  // Create unaccent extension
+  await sql`CREATE EXTENSION IF NOT EXISTS unaccent`.execute(db);
+
+  // Create pg_trgm extension
+  await sql`CREATE EXTENSION IF NOT EXISTS pg_trgm`.execute(db);
+
+  // Create IMMUTABLE wrapper function for unaccent
+  // This allows us to create indexes on unaccented columns for better performance
+  // https://stackoverflow.com/a/11007216/8299075
+  await sql`
+    CREATE OR REPLACE FUNCTION f_unaccent(text) RETURNS text
+    AS $$
+      SELECT unaccent('unaccent', $1);
+    $$ LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT;
+  `.execute(db);
+
+  // Update the pages tsvector trigger to use the immutable function
+  await sql`
+    CREATE OR REPLACE FUNCTION pages_tsvector_trigger() RETURNS trigger AS $$
+    begin
+        new.tsv :=
+                  setweight(to_tsvector('english', f_unaccent(coalesce(new.title, ''))), 'A') ||
+                  setweight(to_tsvector('english', f_unaccent(substring(coalesce(new.text_content, ''), 1, 1000000))), 'B');
+        return new;
+    end;
+    $$ LANGUAGE plpgsql;
+  `.execute(db);
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await sql`
+    CREATE OR REPLACE FUNCTION pages_tsvector_trigger() RETURNS trigger AS $$
+    begin
+        new.tsv :=
+                  setweight(to_tsvector('english', coalesce(new.title, '')), 'A') ||
+                  setweight(to_tsvector('english', coalesce(new.text_content, '')), 'B');
+        return new;
+    end;
+    $$ LANGUAGE plpgsql;
+  `.execute(db);
+
+  await sql`DROP FUNCTION IF EXISTS f_unaccent(text)`.execute(db);
+
+  await sql`DROP EXTENSION IF EXISTS pg_trgm`.execute(db);
+
+  await sql`DROP EXTENSION IF EXISTS unaccent`.execute(db);
+}