Scope block reorg detection to the current chain

Blocks are now stamped with the Bitcoin network name ("main", "test",
"signet") at ingest time. The reconcile loop's Pass 2 skips any stored
block whose chain differs from the node's current chain, preventing
testnet blocks from being falsely orphaned after switching back to
mainnet. Legacy rows with an empty chain field fall through unchanged.

The UI shows a blue "test" / "signet" badge next to blocks from a
non-current network so operators can distinguish cross-chain history
from genuine reorg-orphaned blocks.

api/internal/state/blocks.go

@@ -23,6 +23,7 @@ type BlockRecord struct {
 	Source     string    `json:"source"` // "logmon" for now; "zmq" later
 	ShareDiff  float64   `json:"share_diff,omitempty"`
 	OrphanedAt time.Time `json:"orphaned_at,omitempty"`
+	Chain      string    `json:"chain,omitempty"` // "main", "test", "signet"
 }
 
 // IngestAttemptEvents counts "Possible/Submitting block solve" log
@@ -67,11 +68,20 @@ func (a *Aggregator) IngestBlockEvents(ctx context.Context, events <-chan logmon
 			if !ok {
 				return
 			}
+			// Stamp the chain name at the moment the block is seen so
+			// the reconcile loop can skip it if the node switches networks.
+			a.mu.RLock()
+			currentChain := ""
+			if a.snap.Chain != nil {
+				currentChain = a.snap.Chain.Chain
+			}
+			a.mu.RUnlock()
 			rec := BlockRecord{
 				Height:    ev.Height,
 				FoundAt:   ev.SeenAt,
 				Source:    "logmon",
 				ShareDiff: ev.ShareDiff,
+				Chain:     currentChain,
 			}
 			// Best-effort enrich with hash + coinbase reward via bitcoind.
 			// We look up the hash from height, then fetch the full block
@@ -101,6 +111,7 @@ func (a *Aggregator) IngestBlockEvents(ctx context.Context, events <-chan logmon
 					FoundAt:   rec.FoundAt,
 					Source:    rec.Source,
 					ShareDiff: rec.ShareDiff,
+					Chain:     rec.Chain,
 				})
 				if err != nil {
 					a.Log.Warn("block persist failed", "height", rec.Height, "err", err)
@@ -199,6 +210,18 @@ func (a *Aggregator) reconcileOnce(ctx context.Context) {
 	// matches our record. Don't bother with rows that are already
 	// orphaned — we won't un-orphan, since the network already
 	// chose another chain.
+	//
+	// Skip blocks whose recorded chain doesn't match the current
+	// bitcoind network — they were mined on a different node config
+	// (e.g. testnet) and cannot be checked against mainnet's tip.
+	// A mismatch here is a false positive, not a real reorg.
+	a.mu.RLock()
+	currentChain := ""
+	if a.snap.Chain != nil {
+		currentChain = a.snap.Chain.Chain
+	}
+	a.mu.RUnlock()
+
 	recent, err := a.Store.Recent(64)
 	if err != nil {
 		a.Log.Warn("reconcile: load recent failed", "err", err)
@@ -213,6 +236,13 @@ func (a *Aggregator) reconcileOnce(ctx context.Context) {
 		if b.FoundAt.Before(since) {
 			continue
 		}
+		// Both chain values must be known before we can compare them.
+		// Legacy rows (Chain=="") fall through so existing installs keep
+		// their reorg detection — there was no network switch before this
+		// feature landed.
+		if b.Chain != "" && currentChain != "" && b.Chain != currentChain {
+			continue
+		}
 		lookupCtx, cancel := context.WithTimeout(ctx, 3*time.Second)
 		canonical, herr := a.RPC.GetBlockHash(lookupCtx, b.Height)
 		cancel()
@@ -291,6 +321,7 @@ func (a *Aggregator) loadPersistedBlocks() {
 			Source:     r.Source,
 			ShareDiff:  r.ShareDiff,
 			OrphanedAt: r.OrphanedAt,
+			Chain:      r.Chain,
 		})
 	}
 	a.mu.Lock()

api/internal/store/blocks.go

@@ -28,6 +28,7 @@ type Block struct {
 	Source     string
 	ShareDiff  float64
 	OrphanedAt time.Time // zero value = not orphaned
+	Chain      string    // "main", "test", "signet", or "" for legacy rows
 }
 
 const schema = `
@@ -38,7 +39,8 @@ CREATE TABLE IF NOT EXISTS blocks (
     found_at     INTEGER NOT NULL,
     source       TEXT NOT NULL DEFAULT '',
     share_diff   REAL NOT NULL DEFAULT 0,
-    orphaned_at  INTEGER NOT NULL DEFAULT 0
+    orphaned_at  INTEGER NOT NULL DEFAULT 0,
+    chain        TEXT NOT NULL DEFAULT ''
 );
 CREATE INDEX IF NOT EXISTS blocks_found_at_idx ON blocks(found_at);
 
@@ -83,6 +85,11 @@ func (s *BlockStore) migrate() error {
 			return fmt.Errorf("store: add orphaned_at: %w", err)
 		}
 	}
+	if !have["chain"] {
+		if _, err := s.db.Exec(`ALTER TABLE blocks ADD COLUMN chain TEXT NOT NULL DEFAULT ''`); err != nil {
+			return fmt.Errorf("store: add chain: %w", err)
+		}
+	}
 	return nil
 }
 
@@ -121,9 +128,9 @@ func (s *BlockStore) Close() error {
 // unnoticed.
 func (s *BlockStore) InsertBlock(b Block) (bool, error) {
 	res, err := s.db.Exec(
-		`INSERT OR IGNORE INTO blocks(height, hash, reward_btc, found_at, source, share_diff)
+		`INSERT OR IGNORE INTO blocks(height, hash, reward_btc, found_at, source, share_diff, chain)
-		 VALUES (?, ?, ?, ?, ?, ?)`,
+		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
-		b.Height, b.Hash, b.RewardBT, b.FoundAt.Unix(), b.Source, b.ShareDiff,
+		b.Height, b.Hash, b.RewardBT, b.FoundAt.Unix(), b.Source, b.ShareDiff, b.Chain,
 	)
 	if err != nil {
 		return false, err
@@ -201,7 +208,7 @@ func (s *BlockStore) Recent(limit int) ([]Block, error) {
 		limit = 256
 	}
 	rows, err := s.db.Query(
-		`SELECT height, hash, reward_btc, found_at, source, share_diff, orphaned_at
+		`SELECT height, hash, reward_btc, found_at, source, share_diff, orphaned_at, chain
 		 FROM blocks ORDER BY height DESC LIMIT ?`,
 		limit,
 	)
@@ -213,7 +220,7 @@ func (s *BlockStore) Recent(limit int) ([]Block, error) {
 	for rows.Next() {
 		var b Block
 		var foundUnix, orphanedUnix int64
-		if err := rows.Scan(&b.Height, &b.Hash, &b.RewardBT, &foundUnix, &b.Source, &b.ShareDiff, &orphanedUnix); err != nil {
+		if err := rows.Scan(&b.Height, &b.Hash, &b.RewardBT, &foundUnix, &b.Source, &b.ShareDiff, &orphanedUnix, &b.Chain); err != nil {
 			return nil, err
 		}
 		b.FoundAt = time.Unix(foundUnix, 0).UTC()
@@ -234,7 +241,7 @@ func (s *BlockStore) Recent(limit int) ([]Block, error) {
 // retrying will keep failing.
 func (s *BlockStore) BlocksNeedingEnrichment(since time.Time) ([]Block, error) {
 	rows, err := s.db.Query(
-		`SELECT height, hash, reward_btc, found_at, source, share_diff, orphaned_at
+		`SELECT height, hash, reward_btc, found_at, source, share_diff, orphaned_at, chain
 		 FROM blocks
 		 WHERE found_at >= ? AND (hash = '' OR reward_btc = 0)
 		 ORDER BY height ASC`,
@@ -248,7 +255,7 @@ func (s *BlockStore) BlocksNeedingEnrichment(since time.Time) ([]Block, error) {
 	for rows.Next() {
 		var b Block
 		var foundUnix, orphanedUnix int64
-		if err := rows.Scan(&b.Height, &b.Hash, &b.RewardBT, &foundUnix, &b.Source, &b.ShareDiff, &orphanedUnix); err != nil {
+		if err := rows.Scan(&b.Height, &b.Hash, &b.RewardBT, &foundUnix, &b.Source, &b.ShareDiff, &orphanedUnix, &b.Chain); err != nil {
 			return nil, err
 		}
 		b.FoundAt = time.Unix(foundUnix, 0).UTC()

ui/src/lib/BlocksTable.svelte

@@ -10,6 +10,8 @@
   const explorerBase = $derived(
     explorerBaseFor(snap.data?.chain?.chain, snap.data?.mempool_base_url),
   );
+
+  const currentChain = $derived(snap.data?.chain?.chain ?? "");
 </script>
 
 <section class="card">
@@ -36,6 +38,9 @@
                 {#if b.orphaned_at}
                   <span class="orphan-tag" title="Reorged out of the canonical chain at {b.orphaned_at}">orphaned</span>
                 {/if}
+                {#if b.chain && currentChain && b.chain !== currentChain}
+                  <span class="chain-tag" title="Mined on {b.chain} — current node is {currentChain}">{b.chain}</span>
+                {/if}
               </td>
               <td class="hash-cell">
                 {#if b.hash}
@@ -121,6 +126,18 @@
     text-decoration: none;
     vertical-align: middle;
   }
+  .chain-tag {
+    display: inline-block;
+    margin-left: 0.4em;
+    padding: 0.05em 0.4em;
+    border-radius: 3px;
+    background: rgba(80, 160, 220, 0.15);
+    color: rgb(100, 170, 220);
+    font-size: 0.7em;
+    font-weight: 600;
+    text-decoration: none;
+    vertical-align: middle;
+  }
   .unit {
     color: var(--fg-dim);
     font-size: 0.75em;

ui/src/types.ts

@@ -98,6 +98,9 @@ export type BlockRecord = {
   // longer matches the canonical block at this height (network reorged
   // us out). UI renders these strikethrough.
   orphaned_at?: string; // RFC 3339, omitted when zero
+  // Bitcoin network the block was mined on ("main", "test", "signet").
+  // Absent for legacy rows recorded before this field was added.
+  chain?: string;
 };
 
 export type HashratePoint = {