feat: relevance-ordered search, suggest rows and journal:reindex

- Engine search asks Typesense for the first 250 candidates, re-gates them
  in SQL, counts the gated rows and pages over them in rank order; pages
  after the first are no longer empty. An explicit sort overrides the rank.
- The settings row gates engine search, so it works straight after boot.
- ?fields=suggest serves id, title, slug, a plain-text excerpt,
  featured_image_url and published_at.
- Content is indexed as plain text; Post declares SearchIndexSchema.
- journal:reindex [--fresh] syncs every post into the index.

console/logger.go

@@ -0,0 +1,7 @@
+package console
+
+import "git.golem15.com/golem15/summercms/modules/diary"
+
+// pluginLog is the plugin's logger: its records carry component=journal, so
+// config/log.yaml can raise or lower them (log.components.journal).
+var pluginLog = diary.For("journal")