fix: doctor check skips interactions.jsonl and molecules.jsonl (GH#709) (#739)

The fix for GH#709 updated FindJSONLInDir to skip interactions.jsonl,
but the doctor check in CheckLegacyJSONLFilename was not updated.
This caused `bd doctor` to warn about multiple JSONL files when
both issues.jsonl and interactions.jsonl exist (which is normal
after `bd init`).

Also skip molecules.jsonl which is another system file that shouldn't
be counted as a duplicate issue database.

cmd/bd/doctor/legacy.go

@@ -154,6 +154,8 @@ func CheckLegacyJSONLFilename(repoPath string) DoctorCheck {
 			strings.Contains(lowerName, "~") ||
 			strings.HasPrefix(lowerName, "backup_") ||
 			name == "deletions.jsonl" ||
+			name == "interactions.jsonl" ||
+			name == "molecules.jsonl" ||
 			// Git merge conflict artifacts (e.g., issues.base.jsonl, issues.left.jsonl)
 			strings.Contains(lowerName, ".base.jsonl") ||
 			strings.Contains(lowerName, ".left.jsonl") ||

cmd/bd/doctor/legacy_test.go

@@ -278,6 +278,24 @@ func TestCheckLegacyJSONLFilename(t *testing.T) {
 			expectedStatus: "ok",
 			expectWarning:  false,
 		},
+		{
+			name:           "interactions.jsonl ignored as system file (GH#709)",
+			files:          []string{"issues.jsonl", "interactions.jsonl"},
+			expectedStatus: "ok",
+			expectWarning:  false,
+		},
+		{
+			name:           "molecules.jsonl ignored as system file",
+			files:          []string{"issues.jsonl", "molecules.jsonl"},
+			expectedStatus: "ok",
+			expectWarning:  false,
+		},
+		{
+			name:           "all system files ignored together",
+			files:          []string{"issues.jsonl", "deletions.jsonl", "interactions.jsonl", "molecules.jsonl"},
+			expectedStatus: "ok",
+			expectWarning:  false,
+		},
 	}
 
 	for _, tt := range tests {