fix(sqlite): register fts5 and rtree extensions explicitly

go-sqlite3 v0.35.0 moved the FTS5 and R*Tree/Geopoly extensions into
separate packages, so they are no longer part of the default build. This
broke schemas that use virtual tables, e.g.

    CREATE VIRTUAL TABLE ft USING fts5(b);

which now fails with "no such module: fts5" when the SQLite analyzer
applies migrations.

Add an internal package that registers both extensions as auto
extensions, and import it wherever sqlc opens a SQLite connection, so
they are available on every connection as they were before the bump.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011B9zXEdnMfRMVmWQaJFXVS

Author: claude

internal/cmd/vet_sqlite.go

@@ -2,4 +2,6 @@ package cmd
 
 import (
 	_ "github.com/ncruces/go-sqlite3/driver"
+
+	_ "github.com/sqlc-dev/sqlc/internal/sqlite3ext"
 )

internal/engine/sqlite/analyzer/analyze.go

@@ -16,6 +16,7 @@ import (
 	"github.com/sqlc-dev/sqlc/internal/sql/named"
 	"github.com/sqlc-dev/sqlc/internal/sql/sqlerr"
 	"github.com/sqlc-dev/sqlc/internal/sqlcdebug"
+	_ "github.com/sqlc-dev/sqlc/internal/sqlite3ext"
 )
 
 var debugDatabases = sqlcdebug.New("databases")

internal/sqlite3ext/sqlite3ext.go

@@ -0,0 +1,21 @@
+// Package sqlite3ext registers the SQLite extensions sqlc relies on with
+// github.com/ncruces/go-sqlite3.
+//
+// As of go-sqlite3 v0.35.0 the FTS5 and R*Tree/Geopoly extensions are compiled
+// separately and are no longer part of the default build. Registering them as
+// auto extensions makes them available on every connection, matching the
+// behavior of earlier releases.
+//
+// Import this package for side effects wherever a SQLite connection is opened.
+package sqlite3ext
+
+import (
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/ext/fts5"
+	"github.com/ncruces/go-sqlite3/ext/rtree"
+)
+
+func init() {
+	sqlite3.AutoExtension(fts5.Register)
+	sqlite3.AutoExtension(rtree.Register)
+}

internal/sqltest/sqlite.go

@@ -9,6 +9,7 @@ import (
 	_ "github.com/ncruces/go-sqlite3/driver"
 
 	"github.com/sqlc-dev/sqlc/internal/sql/sqlpath"
+	_ "github.com/sqlc-dev/sqlc/internal/sqlite3ext"
 )
 
 func SQLite(t *testing.T, migrations []string) (*sql.DB, func()) {