conjurer: deploy bot on its own [deploy]-gated image channel

The production bot now tracks conjurer-bot-deploy instead of conjurer-bot,
so it updates only when the conjurer CI promotes a build (commit message
contains [deploy]). Adds the image-updater 'deploy-bot' alias and the
kustomization images entry for it; DEPLOY-BOT.md documents the channel and
the one-time bootstrap. Test bot + librarian keep tracking every build.

Pairs with conjurer#20 (the CI promotion step).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

conjurer/DEPLOY-BOT.md

@@ -23,17 +23,19 @@ bytes). The image-updater's `deploy-bot` alias then bumps this bot's tag.
 So: normal commits update the test bot + librarian; a commit with `[deploy]` in
 its message is the one that also rolls the production bot.
 
-**Bootstrap (first run):** `conjurer-bot-deploy` doesn't exist until the first
-`[deploy]` build. Either land one commit with `[deploy]` in the message, or seed
-it once by hand:
+**Already bootstrapped:** the channel was seeded by the first `[deploy]` commit
+(the merge of conjurer#20), which promoted `conjurer-bot-deploy:fbd1ec9f` — the
+tag pinned in `kustomization.yaml`. From here the image-updater keeps it current
+on each future `[deploy]` commit. Note the librarian is shared and still tracks
+latest, so mind large bot⇄librarian version skews.
+
+If you ever need to seed a tag by hand:
 ```bash
-docker pull  gitea.czernobog.pl/gitea/conjurer-bot:ac16b77f
-docker tag   gitea.czernobog.pl/gitea/conjurer-bot:ac16b77f \
-             gitea.czernobog.pl/gitea/conjurer-bot-deploy:ac16b77f
-docker push  gitea.czernobog.pl/gitea/conjurer-bot-deploy:ac16b77f
+docker pull gitea.czernobog.pl/gitea/conjurer-bot:<sha>
+docker tag  gitea.czernobog.pl/gitea/conjurer-bot:<sha> \
+            gitea.czernobog.pl/gitea/conjurer-bot-deploy:<sha>
+docker push gitea.czernobog.pl/gitea/conjurer-bot-deploy:<sha>
 ```
-(match the tag in `kustomization.yaml`). Note the librarian is shared, so it
-still tracks latest — mind large bot⇄librarian version skews.
 
 ## One-time setup
 

conjurer/kustomization.yaml

@@ -8,11 +8,12 @@ resources:
   - deploy-bot-backup.yaml
 images:
   - name: gitea.czernobog.pl/gitea/conjurer-librarian
-    newTag: f4dea535
+    newTag: fbd1ec9f
   - name: gitea.czernobog.pl/gitea/conjurer-bot
-    newTag: f4dea535
+    newTag: fbd1ec9f
   # Production bot channel - only bumped when a [deploy]-tagged build appears.
-  # Placeholder tag; the image-updater sets the real one once the first
-  # [deploy] build (merging conjurer#20) creates conjurer-bot-deploy.
+  # Bootstrapped to fbd1ec9f: that's the image the first [deploy] build (merge
+  # of conjurer#20) promoted to conjurer-bot-deploy. From here the image-updater
+  # keeps it current across future [deploy] commits.
   - name: gitea.czernobog.pl/gitea/conjurer-bot-deploy
-    newTag: f4dea535
+    newTag: fbd1ec9f