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.metadata.json

@@ -0,0 +1,37 @@
+{
+  "requested_model": "claude-opus-5",
+  "requested_effort": "max",
+  "cli_version": "2.1.270",
+  "baseline": "9ebe81c1b3611f9cc73e676b5b741c2be62c467a",
+  "plan": "plan-v1.md",
+  "plan_sha256": "7af5705ebbfb0a375956d38dba059095dc16e24558290b1bd35a6ce85b9e1f96",
+  "status": "completed",
+  "started_at": "2026-09-15T15:44:49.861232+00:00",
+  "raw_output": "/Users/vonng/tmp/silo-r7-20260915-ad51/opus-v1.jsonl",
+  "stderr": "/Users/vonng/tmp/silo-r7-20260915-ad51/opus-v1.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"
+  ],
+  "observed_tool_attempts": [
+    "Glob",
+    "Grep",
+    "Read",
+    "Write"
+  ],
+  "subtype": "success",
+  "is_error": false,
+  "duration_ms": 309465,
+  "num_turns": 62,
+  "session_id": "10f1e9b3-7120-4a1f-94d9-e53745849cd1",
+  "raw_sha256": "b749be2acbec45b978907849c741e1f71994b0ad4e13d5b5204f429c9ba408b3",
+  "review_sha256": "d832e461291f0ec32455ade97c9bf9cd02d31812642a4b9254dd5e06ab1cc82b",
+  "verdict": "APPROVE_WITH_NONBLOCKING_NOTES",
+  "blocking_findings": 0,
+  "completed_at": "2026-09-15T15:51:03.390714+00:00",
+  "auxiliary_model_ids": [
+    "claude-haiku-4-5-20251001",
+    "claude-opus-5"
+  ],
+  "note": "Actual reviewer assistant messages all identify claude-opus-5. CLI plan mode attempted Write to a Claude plan artifact, but Write was disabled; final review was returned as text. No product changes."
+}