chore(bots): bump engine pin to 654a31d0 (per-bot models) (#905)

chore(bots): bump engine pin d05dcb11 -> 654a31d0

Move all bots to engine main (654a31d0), 30 commits ahead of the current pin.
This repo already runs the modern daily-cron retrospective + closed loop; this
brings the pinned engine in line with the sibling driver repos (kernel + the
go/nodejs/jdbc/odbc learning PRs), whose engine was bumped to the same SHA.

The main addition since d05dcb11 is per-bot model selection (default opus-4.8).
SDK/CLI locked versions (0.2.102 / 2.1.61) are unchanged at 654a31d0, so this is
a SHA-only bump — no install-bot-engine edit needed.

Co-authored-by: Isaac

Signed-off-by: eric-wang-1990 <e.wang@databricks.com>

Author: eric-wang-1990

.github/actions/bot-prelude/action.yml

@@ -31,7 +31,7 @@ inputs:
     # value to move every bot to a new engine commit; never @main.
     description: 'Engine commit SHA (full 40-char) to install.'
     required: false
-    default: 'd05dcb113332401b4aee8d6aa05c7107399ad44f'
+    default: '654a31d0d26d2b77bcb58e84f1e4abe018f9fd5a'
   engine-repo:
     description: 'owner/name of the engine repo.'
     required: false