state: add SOPS-encrypted terraform state to git

- SOPS + age encrypts all 101 .tfstate files (JSON-aware: keys visible, values encrypted)
- scripts/state-sync: encrypt/decrypt/commit wrapper
- scripts/tg: auto-decrypt before ops, auto-encrypt+commit after apply/destroy
- terragrunt.hcl: -backup=- prevents backup file accumulation
- .gitignore: track .tfstate.enc, ignore plaintext .tfstate
- Cleaned 964MB of stale backups (state/backups/, .backup files)

scripts/state-sync

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+STATE_DIR="$REPO_ROOT/state/stacks"
+
+cmd="${1:-help}"
+stack="${2:-}"  # optional: operate on single stack
+
+encrypt_state() {
+  local dir="$1"
+  local src="$dir/terraform.tfstate"
+  local dst="$dir/terraform.tfstate.enc"
+  [ -f "$src" ] || return 0
+  # Only re-encrypt if state is newer than encrypted version
+  if [ ! -f "$dst" ] || [ "$src" -nt "$dst" ]; then
+    sops -e --input-type json --output-type json "$src" > "$dst"
+  fi
+}
+
+decrypt_state() {
+  local dir="$1"
+  local src="$dir/terraform.tfstate.enc"
+  local dst="$dir/terraform.tfstate"
+  [ -f "$src" ] || return 0
+  sops -d --input-type json --output-type json "$src" > "$dst"
+}
+
+case "$cmd" in
+  encrypt)
+    if [ -n "$stack" ]; then
+      encrypt_state "$STATE_DIR/$stack"
+    else
+      for dir in "$STATE_DIR"/*/; do
+        encrypt_state "$dir"
+      done
+    fi
+    ;;
+  decrypt)
+    if [ -n "$stack" ]; then
+      decrypt_state "$STATE_DIR/$stack"
+    else
+      for dir in "$STATE_DIR"/*/; do
+        decrypt_state "$dir"
+      done
+    fi
+    ;;
+  commit)
+    # Encrypt all changed state, then git add + commit
+    "$0" encrypt
+    cd "$REPO_ROOT"
+    git add state/stacks/*/terraform.tfstate.enc
+    if ! git diff --cached --quiet; then
+      git commit -m "state: update encrypted terraform state"
+    fi
+    ;;
+  help)
+    echo "Usage: state-sync {encrypt|decrypt|commit} [stack-name]"
+    ;;
+esac