fix(replication): preserve normalized replica metadata

Restore only the six replication-specific metadata fields after trust
validation, so streaming uploads retain their actual content encoding and
Snowball entries do not inherit ordinary metadata from the outer archive.

Include helper, authenticated PUT/COPY/multipart and Snowball regressions,
plus the R7 investigation, actual Opus 5 consensus and local verification.
The production change is based on PR #187 by Mikhail Khadarenka.

Co-authored-by: Mikhail Khadarenka <chodorenko@gmail.com>
Signed-off-by: Feng Ruohang <rh@vonng.com>

docs/investigations/r7/review/opus-v1-confirmation.metadata.json

@@ -0,0 +1,36 @@
+{
+  "requested_model": "claude-opus-5",
+  "requested_effort": "max",
+  "cli_version": "2.1.270",
+  "baseline": "9ebe81c1b3611f9cc73e676b5b741c2be62c467a",
+  "plan": "plan-v1.md",
+  "plan_sha256": "7af5705ebbfb0a375956d38dba059095dc16e24558290b1bd35a6ce85b9e1f96",
+  "addendum": "plan-v1.dispositions.md",
+  "addendum_sha256": "d32d30f8a420f904da6ee039f0461d6281e7da44bd805d416b4970d071f0af32",
+  "status": "completed",
+  "started_at": "2026-09-15T15:51:25.514239+00:00",
+  "raw_output": "/Users/vonng/tmp/silo-r7-20260915-ad51/opus-v1-confirmation.jsonl",
+  "stderr": "/Users/vonng/tmp/silo-r7-20260915-ad51/opus-v1-confirmation.stderr.log",
+  "command": "claude --print --model claude-opus-5 --effort max --safe-mode --permission-mode plan --tools Read,Grep,Glob --strict-mcp-config --no-session-persistence --output-format stream-json --verbose --add-dir /Users/vonng/tmp/silo-r7-20260915-ad51",
+  "actual_assistant_models": [
+    "claude-opus-5"
+  ],
+  "subtype": "success",
+  "is_error": false,
+  "duration_ms": 57910,
+  "num_turns": 18,
+  "session_id": "9b4140a8-140f-4d94-9a59-9983346709fd",
+  "raw_sha256": "2e2db44411a0b367607b73a2f7fe38c5125f49294f496d603c8ed4975c549bba",
+  "review_sha256": "a471ca03b6e68d77d01dede8c6d1a8f989bceed9f7eeb99fc36634c025eb3541",
+  "verdict": "APPROVE",
+  "blocking_findings": 0,
+  "completed_at": "2026-09-15T15:53:09.806502+00:00",
+  "auxiliary_model_ids": [
+    "claude-haiku-4-5-20251001",
+    "claude-opus-5"
+  ],
+  "observed_tool_attempts": [
+    "Grep",
+    "Read"
+  ]
+}