refactor(release): use pretty download_url from /releases/{id} API

Gitea's POST /releases/{id}/assets endpoint returns an internal
/attachments/<uuid> URL. GET /releases/{id} returns the pretty
/<owner>/<repo>/releases/download/<tag>/<name> URL for the same asset.

Both resolve to the same bytes (verified: 207949 for 1.2.0 zip).
Pretty URL is preferred: filename is visible in the URL (better for
WP admin «View version details» and manual downloads), consistent
across Gitea instances (UUID format is git.netranking.ru-specific
Postgres attachment storage).

Also: switch `echo "$VAR" | jq` to `jq ... <<< "$VAR"`
herestring for CREATE_RESPONSE parsing — macOS /bin/echo can
interpret backslash-escapes in multi-line JSON bodies and corrupt
jq input.

wp-plugin-info.json for 1.2.0 patched in-place to use the pretty URL
for consistency with future releases. Both URLs continue to work;
domработница.рус's next PUC poll will refresh its local transient
to the pretty URL (version comparison stays 1.2.0 == 1.2.0, so no
update notice).

Closes cf7stg-pmf (T20).

wp-plugin-info.json

@@ -2,7 +2,7 @@
   "name": "CF7 Spam → Telegram",
   "slug": "cf7-spam-to-telegram",
   "version": "1.2.0",
-  "download_url": "https://git.netranking.ru/attachments/a04cdb20-7e80-4703-8c30-1000e5945e8b",
+  "download_url": "https://git.netranking.ru/bryzgalov/cf7-spam-to-telegram/releases/download/v1.2.0/cf7-spam-to-telegram-1.2.0.zip",
   "homepage": "https://git.netranking.ru/bryzgalov/cf7-spam-to-telegram",
   "requires": "6.0",
   "tested": "6.9",