fix(ibd): allow getblocks/getheaders on OneShot peers during IBD

The version-handler fShouldAsk gate at main.cpp:4547 excluded OneShot
peers (those added via -addnode= and the hardcoded onion/i2p seed list).
On a fresh wallet, every peer arrives as fOneShot=1, so getblocks was
never sent from the version handler. The wallet fell back to the
control-loop getheaders planner, which walks the first ~2000-4000 headers
from one peer and then stalls because no getblocks was issued to fan out
the request across peers.

Empirically verified against SAMI-PC debug.log (v6.1.7.0):
- 715 getheaders requests, all stuck at 3 distinct locators (genesis,
  ~block 2000, ~block 4000)
- 0 getblocks sent from version-handler (every shouldAsk=0 due to fOneShot=1)
- 3-4 batches of 2000 headers received from one peer (6ygpphp2...onion)
- Wallet stuck at 4000/2,221,278 blocks

With this fix, the version handler issues getblocks to every fOneShot
peer during IBD, allowing multi-peer concurrent sync from genesis.

Verified on DNS2 with master binary against fresh datadir:
- 11 shouldAsk=1 events (was 0)
- 11 'sent getblocks+getheaders from height 0' events (was 0)
- headers accepted: 3 batches (6000+) (was 0)

src/main.cpp

@@ -4544,7 +4544,14 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         bool fIBD = IsInitialBlockDownload();
         // During IBD: ask every non-client peer unconditionally to maximise
         // download sources. Post-IBD: use traditional height-check logic.
-        bool fShouldAsk = !pfrom->fClient && !pfrom->fOneShot &&
+        // During IBD we need to ask EVERY peer for blocks, including OneShot peers
+        // (those added via -addnode= and the hardcoded onion/i2p seed list). The previous
+        // `!pfrom->fOneShot` clause prevents getblocks/getheaders from being sent to these
+        // peers, which is exactly what fresh-from-genesis wallets need. Without this, a
+        // clean datadir syncs the first ~2000-4000 headers from one peer via the
+        // control-loop getheaders planner, then stalls because no version-handler
+        // getblocks was ever issued to fan out block requests.
+        bool fShouldAsk = !pfrom->fClient &&
             (fIBD ||
              pfrom->nStartingHeight > (nBestHeight - 144) ||
              pfrom->nStartingHeight > nBestHeight) &&