fix: shrink immich-media to 1400Gi, real disk headroom smaller than assumed

2000Gi didn't schedule - "insufficient storage; tags not fulfilled".
The cp-3 HDD's real usable capacity (~3724GiB) minus paperless-media's
2000Gi and ~231GiB of other apps' default-class replicas that Longhorn
placed here anyway (tags only pull matching volumes in, don't exclude
others when the untagged pool elsewhere is full) only leaves ~1493Gi
of real scheduling headroom. 1400Gi fits with margin.

k8s/apps/immich/pvc.yaml

@@ -1,10 +1,14 @@
 # Two volumes:
 #
 # - media: original photos/videos + generated thumbnails/encoded videos.
-#   Shares the cp-3 USB HDD with paperless-media - the 4TB disk is split
-#   2TB/2TB between the two (see k8s/apps/paperless/pvc.yaml), same
-#   StorageClass/disk tag, single replica (single disk, no redundancy
-#   possible - same tradeoff paperless already accepts).
+#   Shares the cp-3 USB HDD with paperless-media, same StorageClass/disk tag,
+#   single replica (single disk, no redundancy possible - same tradeoff
+#   paperless already accepts). Sized 1400Gi, not 2000Gi: the disk's real
+#   usable capacity (~3724GiB, formatting overhead) minus paperless-media's
+#   2000Gi and ~231GiB of other apps' default-class replicas that Longhorn
+#   placed here anyway (disk tags only pull matching volumes in, they don't
+#   exclude non-matching ones when the untagged pool elsewhere is full) only
+#   leaves ~1493Gi of real scheduling headroom right now.
 # - ml-cache: downloaded ML model weights for immich-machine-learning
 #   (face detection / CLIP embeddings). Small, disposable (re-downloads on
 #   loss), but persisted so a pod restart doesn't re-pull multi-GB models -
@@ -19,7 +23,7 @@ spec:
   storageClassName: longhorn-paperless-media
   resources:
     requests:
-      storage: 2000Gi
+      storage: 1400Gi
 ---
 apiVersion: v1
 kind: PersistentVolumeClaim