Update default blob-threshold from 1MB to 100KB in docs

Matches zodb-pgjsonb 1.3.2 which lowered the default to reduce WAL pollution.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jensens

CHANGES.md

@@ -2,6 +2,10 @@
 
 ## 2.4.1 (unreleased)
 
+- Docs: Update PGJsonb default `blob-threshold` from 1MB to 100KB in docs
+  (matching zodb-pgjsonb 1.4.0).
+  [@jensens]
+
 - Feature: Generate generic `convert-import.conf` and `convert-export.conf`
   for all non-filestorage backends (RelStorage, PGJsonb, ZEO) using the
   storage-agnostic [zodb-convert](https://pypi.org/project/zodb-convert/)

docs/sources/explanation/blob-handling.md

@@ -86,7 +86,7 @@ with no filesystem dependencies.
 For deployments with large or numerous blobs, PGJsonb supports tiering
 blobs to S3-compatible object storage:
 
-- Blobs smaller than `db_pgjsonb_blob_threshold` (default: 1 MB) stay in
+- Blobs smaller than `db_pgjsonb_blob_threshold` (default: 100 KB) stay in
   PostgreSQL `bytea`
 - Blobs exceeding the threshold are uploaded to S3
 - A local cache directory avoids repeated S3 downloads

docs/sources/how-to/configure-pgjsonb.md

@@ -82,7 +82,7 @@ default_context:
     db_pgjsonb_s3_region: us-east-1
     db_pgjsonb_s3_access_key: minio-access-key
     db_pgjsonb_s3_secret_key: minio-secret-key
-    db_pgjsonb_blob_threshold: 1MB
+    db_pgjsonb_blob_threshold: 100KB
     db_pgjsonb_blob_cache_dir: /var/cache/zodb-blobs
     db_pgjsonb_blob_cache_size: 2GB
 ```

docs/sources/reference/database-pgjsonb.md

@@ -72,7 +72,7 @@ the `zodb-pgjsonb[s3]` extra to be installed.
 | `db_pgjsonb_s3_access_key` | *(unset)* | string |
 | `db_pgjsonb_s3_secret_key` | *(unset)* | string |
 | `db_pgjsonb_s3_use_ssl` | `true` | `true`, `false` |
-| `db_pgjsonb_blob_threshold` | *(unset, default `1MB`)* | byte-size (KB, MB, GB) |
+| `db_pgjsonb_blob_threshold` | *(unset, default `100KB`)* | byte-size (KB, MB, GB) |
 | `db_pgjsonb_blob_cache_dir` | *(unset)* | path |
 | `db_pgjsonb_blob_cache_size` | *(unset, default `1GB`)* | byte-size (KB, MB, GB) |