cache knobs: env-parameterize geth/op-geth --cache (default 1024 = geth's own), l2geth --cache (default 8192 = previous hardcoded), nethermind MEMORYHINT (default 2048000000)

All defaults preserve current effective behavior - this deploy is a rendering no-op
until a host_var overrides a value. Part of the resource-optimizer knob rollout
(resource-optimizer/knob-manifest.yaml is the registry; verify_manifest.py enforces
default sync between templates and envfile).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

linea/geth/linea-sepolia-geth-pruned-pebble-path.yml

@@ -57,6 +57,7 @@ services:
     entrypoint: /bin/sh -c '[ -f /config/genesis.json ] && geth --db.engine=pebble --gcmode=full --datadir /root/.ethereum init --state.scheme=path /config/genesis.json; exec geth "$@"' --
     command:
       - --bootnodes=enode://6f20afbe4397e51b717a7c1ad3095e79aee48c835eebd9237a3e8a16951ade1fe0e66e981e30ea269849fcb6ba03d838da37f524fabd2a557474194a2e2604fa@18.221.100.27:31002,enode://ce1e0d8e0500cb5c0ac56bdcdafb2d6320c3a2c5125b5ccf12f5dfc9b47ee74acbcafc32559017613136c9c36a0ce74ba4f83b7fb8244f099f3b15708d9d3129@3.23.75.47:31000,enode://1b026a5eb0ae74300f58987d235ef0e3a550df963345cb3574be3b0b54378bd11f14dfd515a8976f2c2d2826090e9507b8ccc24f896a9ffffffcabcfd996a733@3.129.120.128:31001
+      - --cache=${LINEA_SEPOLIA_GETH_PRUNED_PEBBLE_PATH_CACHE:-1024}
       - --datadir=/root/.ethereum
       - --db.engine=pebble
       - --gcmode=full