Paragon: move module SQL to AC's data/sql/db-* layout for auto-update

AzerothCore's DBUpdater scans modules/<mod>/data/sql/db-{world,characters,auth}/
(see src/server/database/Updater/UpdateFetcher.cpp). The previous
modules/mod-paragon/sql/{world,characters}/base/ layout was non-standard
and skipped by the updater, so a fresh deploy never had Paragon tables
created automatically.

Move all five SQL files into the standard layout. Files are idempotent
(CREATE TABLE IF NOT EXISTS plus a DELETE+INSERT for the cost table)
and now apply on every dbimport / worldserver start, recorded by hash
in <db>.updates so re-runs are skipped.

Update BUILD-NATIVE.md to drop the manual mysql import section, and
document the SQL layout in the mod-paragon README.

Co-authored-by: Cursor <cursoragent@cursor.com>

modules/mod-paragon/README.md

@@ -30,3 +30,14 @@ Auto-detected by `modules/CMakeLists.txt` (`GetModuleSourceList` globs
 every subdirectory). No additional CMake plumbing is needed; rebuild
 the worldserver image and the loader symbol `Addmod_paragonScripts`
 gets linked into the static `modules` target.
+
+## SQL layout
+
+SQL files live under `data/sql/db-world/base/` and
+`data/sql/db-characters/base/` — the standard AzerothCore module path
+that the built-in DBUpdater scans (see
+`src/server/database/Updater/UpdateFetcher.cpp`). Files placed there
+are applied automatically by `worldserver` / `dbimport` on startup and
+recorded by hash in the `updates` table of the target database, so
+re-runs are idempotent. Any new SQL added under those directories will
+be picked up on the next container/server start without manual import.