hydration with pack (#1016)

- Feature: Hub hydration packs small files into raw CAS pack blobs to reduce request count for modules dominated by tiny metadata files
  - `--hub-hydration-enable-pack` (Lua: `hub.hydration.enablepack`, default true)
  - `--hub-hydration-pack-threshold-bytes` (Lua: `hub.hydration.packthresholdbytes`, default 256 KiB)
  - `--hub-hydration-max-pack-bytes` (Lua: `hub.hydration.maxpackbytes`, default 4 MiB)
- Feature: Hub hydration and dehydration can be disabled per direction
  - `--hub-enable-hydration` (Lua: `hub.enablehydration`, default true)
  - `--hub-enable-dehydration` (Lua: `hub.enabledehydration`, default true)
- Feature: Hub hydration accepts a configurable file exclude list via `HydrationOptions` `excludes` (array of wildcards). Built-in defaults skip transient runtime files (`.lock`, `.sentry-native/*`, `state_marker`, `*.bak`, `gc/reserve.gc`, `auth/*`) so they no longer participate in dehydrate scans. Override semantics: a present field replaces the default outright; explicit `[]` opts out of all defaults.
- Improvement: Hub hydration completion logs now report per-request average and max latency, peak in-flight workers, queue wait, and hash-cache hit percentage; loose and pack-blob transfers are reported separately
- Improvement: Hub hydration pre-creates unique parent directories before scheduling parallel writes
- Improvement: S3 hydration retries transient HTTP failures (timeouts, 429 throttling, 5xx server errors, connection errors) up to 3 times via the HTTP client retry layer
- Improvement: S3 hydration multipart chunk size is persisted in `state.cbo` per module so hydrate replays the partitioning used at dehydrate; default raised to 64 MiB (was 32 MiB)
- Improvement: Hub hydration `Obliterate` retries backend delete once before falling back to local cleanup

1 files changed, 15 insertions, 0 deletions

diff --git a/scripts/test_scripts/hub/perf_configs/instance.lua b/scripts/test_scripts/hub/perf_configs/instance.lua
new file mode 100644
index 000000000..1251997db
--- /dev/null
+++ b/scripts/test_scripts/hub/perf_configs/instance.lua
@@ -0,0 +1,15 @@
+network = {
+  httpserverthreads = 4, -- default: auto
+}
+
+gc = {
+  enabled = false, -- default: true. hub triggers GC at deprovision, no need for periodic GC
+}
+
+cache = {
+  bucket = {
+    memlayer = {
+      sizethreshold = 0, -- default: 1024. 0 disables memlayer entirely
+    },
+  },
+}