Fix two long-standing bugs in the vault-init PreSync hook script

Both pre-existing (not from today's work), found while cleaning up a
recurring stale-pod pattern (a fresh vault-init Job failing on every
sync of the vault Application):

1. Init-detection was always broken: `vault status -format=json`
   pretty-prints with a space after colons ("initialized": true), but
   the parser (grep -o '"initialized":[a-z]*' | cut -d: -f2) required
   no space - it always matched empty, so `initialized`/`sealed` were
   always blank regardless of real state. Every run concluded "not
   initialized" and tried to re-init, which correctly fails once Vault
   already has been ("Vault is already initialized"). Switched to jq.
   Separately, the old `|| echo '{}'` fallback also discarded valid
   JSON on vault status's normal non-zero exit codes (2 = sealed) -
   fixed too, though the parsing bug was the actual blocker.

2. `vault_exec` wraps `kubectl exec` without `-i`, so the heredoc piped
   into `vault policy write NAME -` never reached the remote command -
   vault saw an empty policy body. Never previously reached in
   practice since bug #1 always failed the script earlier. Added -i.

Verified end-to-end with a one-off Job run: script now correctly
detects the already-initialized state and completes successfully,
including the policy/role writes that were previously unreachable.

infrastructure/vault/manifests/vault-init-configmap.yaml

@@ -26,7 +26,12 @@ data:
 
     # Helper: run vault CLI inside the vault pod
     vault_exec() {
-      kubectl -n "$VAULT_NS" exec "$VAULT_POD" -- env VAULT_ADDR=http://127.0.0.1:8200 vault "$@"
+      # -i forwards stdin - needed for the heredoc-piped `vault policy write
+      # NAME -` call below. Without it, `kubectl exec` never passes stdin
+      # through and vault sees an empty policy body. This was unreachable
+      # until the init-detection fix above (the script always failed earlier,
+      # every run, before ever getting this far).
+      kubectl -n "$VAULT_NS" exec -i "$VAULT_POD" -- env VAULT_ADDR=http://127.0.0.1:8200 vault "$@"
     }
 
     # --- Wait for vault-0 pod to be ready ---
@@ -45,10 +50,26 @@ data:
     sleep 5
 
     # --- Check init/seal status ---
+    # `vault status` legitimately exits non-zero for normal states (2 = sealed,
+    # still prints valid JSON) as well as real failures (1 = can't connect, no
+    # output). The old `|| echo '{}'` fallback couldn't tell those apart - it
+    # discarded valid "already initialized, just sealed" JSON on exit 2 too,
+    # which made this script wrongly conclude "not initialized" and attempt to
+    # re-init an already-initialized Vault (always fails: "Vault is already
+    # initialized"). Only fall back to {} when there's truly no output.
     echo "==> Checking Vault status..."
-    status_json="$(vault_exec status -format=json 2>/dev/null || echo '{}')"
-    initialized="$(echo "$status_json" | grep -o '"initialized":[a-z]*' | cut -d: -f2 || echo "")"
-    sealed="$(echo "$status_json" | grep -o '"sealed":[a-z]*' | cut -d: -f2 || echo "")"
+    status_json="$(vault_exec status -format=json 2>/dev/null)"
+    if [ -z "$status_json" ]; then
+      status_json="{}"
+    fi
+    # jq, not grep/cut - `vault status -format=json` pretty-prints with a space
+    # after each colon ("initialized": true), which the old grep -o
+    # '"initialized":[a-z]*' pattern never matched (no space in the pattern) -
+    # initialized/sealed silently parsed as empty strings on every run
+    # regardless of actual Vault state, which is the real reason this script
+    # always tried to re-init an already-initialized Vault.
+    initialized="$(echo "$status_json" | jq -r '.initialized // empty')"
+    sealed="$(echo "$status_json" | jq -r '.sealed // empty')"
 
     root_token=""
     unseal_key=""