instagram-poster: force_conflicts on ESO manifests (fix apply)

The ESO v1 migration (2026-06-22) made the external-secrets controller own
.spec.refreshInterval via server-side apply, so terraform apply of the two
ExternalSecret manifests fails with a field-manager conflict (Woodpecker #348),
which blocked the replicas=0 scale-down from landing. Add force_conflicts=true
to both, matching the grafana/woodpecker/traefik fix applied to other stacks
the same day.

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

stacks/instagram-poster/modules/instagram-poster/main.tf

@@ -35,6 +35,14 @@ resource "kubernetes_namespace" "instagram_poster" {
 #     - immich_tag_instagram      (optional — auto-resolved if missing)
 #     - immich_tag_posted         (optional — auto-resolved if missing)
 resource "kubernetes_manifest" "external_secret" {
+  # The external-secrets controller takes server-side-apply ownership of
+  # .spec.refreshInterval, so a plain TF apply conflicts. force_conflicts lets
+  # TF win (values match, so it's stable) — same pattern as grafana/woodpecker/
+  # traefik/k8s-version-upgrade. Surfaced 2026-06-24 by the first IG apply since
+  # the ESO v1 migration (the scale-to-0 push).
+  field_manager {
+    force_conflicts = true
+  }
   manifest = {
     apiVersion = "external-secrets.io/v1"
     kind       = "ExternalSecret"
@@ -139,6 +147,11 @@ resource "kubernetes_manifest" "external_secret" {
 # ESO refreshes the K8s Secret every 15m. `reloader.stakater.com/match`
 # bounces the pod when the password changes.
 resource "kubernetes_manifest" "benchmark_db_external_secret" {
+  # See external_secret above — ESO owns .spec.refreshInterval; force_conflicts
+  # lets the TF apply win instead of erroring on the field-manager conflict.
+  field_manager {
+    force_conflicts = true
+  }
   manifest = {
     apiVersion = "external-secrets.io/v1"
     kind       = "ExternalSecret"